Aggressive angiomyxoma with diffusion-weighted magnetic resonance imaging and dynamic contrast enhancement: a case report and review of the literature.

PubMed

Brunelle, S; Bertucci, F; Chetaille, B; Lelong, B; Piana, G; Sarran, A

2013-05-01

Aggressive angiomyxoma (AA) is a rare benign soft tissue tumour usually affecting the pelvis and perineum of young women. Magnetic resonance imaging (MRI) is crucial in the management of AA patients for its diagnostic contribution and for the preoperative assessment of the actual tumour extension. Given the current development of less aggressive therapeutics associated with a higher risk of recurrence, close follow-up with MRI is fundamental after treatment. In this context, diffusion-weighted (DW) imaging has already shown high efficacy in the detection of early small relapses in prostate or rectal cancer. We report here a case of pelvic AA in a 51-year-old woman examined with dynamic contrast enhancement and DW-MRI, including apparent diffusion coefficient mapping and calculation. To our knowledge, this is the first description of DW-MRI in AA reported in the literature. Here, knowledge about imaging features of AA will be reviewed and expanded.

Characterization of the collagen component of cartilage repair tissue of the talus with quantitative MRI: comparison of T2 relaxation time measurements with a diffusion-weighted double-echo steady-state sequence (dwDESS).

PubMed

Kretzschmar, M; Bieri, O; Miska, M; Wiewiorski, M; Hainc, N; Valderrabano, V; Studler, U

2015-04-01

The purpose of this study was to characterize the collagen component of repair tissue (RT) of the talus after autologous matrix-induced chondrogenesis (AMIC) using quantitative T2 and diffusion-weighted imaging. Mean T2 values and diffusion coefficients of AMIC-RT and normal cartilage of the talus of 25 patients with posttraumatic osteochondral lesions and AMIC repair were compared in a cross-sectional design using partially spoiled steady-state free precession (pSSFP) for T2 quantification, and diffusion-weighted double-echo steady-state (dwDESS) for diffusion measurement. RT and cartilage were graded with modified Noyes and MOCART scores on morphological sequences. An association between follow-up interval and quantitative MRI measures was assessed using multivariate regression, after stratifying the cohort according to time interval between surgery and MRI. Mean T2 of the AMIC-RT and cartilage were 43.1 ms and 39.1 ms, respectively (p = 0.26). Mean diffusivity of the RT (1.76 μm(2)/ms) was significantly higher compared to normal cartilage (1.46 μm(2)/ms) (p = 0.0092). No correlation was found between morphological and quantitative parameters. RT diffusivity was lowest in the subgroup with follow-up >28 months (p = 0.027). Compared to T2-mapping, dwDESS demonstrated greater sensitivity in detecting differences in the collagen matrix between AMIC-RT and cartilage. Decreased diffusivity in patients with longer follow-up times may indicate an increased matrix organization of RT. • MRI is used to assess morphology of the repair tissue during follow-up. • Quantitative MRI allows an estimation of biochemical properties of the repair tissue. • Differences between repair tissue and cartilage were more significant with dwDESS than T2 mapping.

Differentiation of Central Lung Cancer from Atelectasis: Comparison of Diffusion-Weighted MRI with PET/CT

PubMed Central

Yang, Rui-Meng; Li, Long; Wei, Xin-Hua; Guo, Yong-Mei; Huang, Yun-Hai; Lai, Li-Sha; Chen, A-Mei; Liu, Guo-Shun; Xiong, Wei-Feng; Luo, Liang-Ping; Jiang, Xin-Qing

2013-01-01

Objective Prospectively assess the performance of diffusion-weighted magnetic resonance imaging (DW-MRI) for differentiation of central lung cancer from atelectasis. Materials and Methods 38 consecutive lung cancer patients (26 males, 12 females; age range: 28–71 years; mean age: 49 years) who were referred for thoracic MR imaging examinations were enrolled. MR examinations were performed using a 1.5-T clinical scanner and scanning sequences of T1WI, T2WI, and DWI. Cancers and atelectasis were measured by mapping of the apparent diffusion coefficients (ADCs) obtained with a b-value of 500 s/mm2. Results PET/CT and DW-MR allowed differentiation of tumor and atelectasis in all 38 cases, but T2WI did not allow differentiation in 9 cases. Comparison of conventional T2WI and DW-MRI indicated a higher contrast noise ratio of the central lung carcinoma than the atelectasis by DW-MRI. ADC maps indicated significantly lower mean ADC in the central lung carcinoma than in the atelectasis (1.83±0.58 vs. 2.90±0.26 mm2/s, p<0.0001). ADC values of small cell lung carcinoma were significantly greater than those from squamous cell carcinoma and adenocarcinoma (p<0.0001 for both). Conclusions DW-MR imaging provides valuable information not obtained by conventional MR and may be useful for differentiation of central lung carcinoma from atelectasis. Future developments may allow DW-MR imaging to be used as an alternative to PET-CT in imaging of patients with lung cancer. PMID:23593186

Choice of reference measurements affects quantification of long diffusion time behaviour using stimulated echoes.

PubMed

Kleinnijenhuis, Michiel; Mollink, Jeroen; Lam, Wilfred W; Kinchesh, Paul; Khrapitchev, Alexandre A; Smart, Sean C; Jbabdi, Saad; Miller, Karla L

2018-02-01

To demonstrate how reference data affect the quantification of the apparent diffusion coefficient (ADC) in long diffusion time measurements with diffusion-weighted stimulated echo acquisition mode (DW-STEAM) measurements, and to present a modification to avoid contribution from crusher gradients in DW-STEAM. For DW-STEAM, reference measurements at long diffusion times have significant b 0 value, because b = 0 cannot be achieved in practice as a result of the need for signal spoiling. Two strategies for acquiring reference data over a range of diffusion times were considered: constant diffusion weighting (fixed-b 0 ) and constant gradient area (fixed-q 0 ). Fixed-b 0 and fixed-q 0 were compared using signal calculations for systems with one and two diffusion coefficients, and experimentally using data from postmortem human corpus callosum samples. Calculations of biexponential diffusion decay show that the ADC is underestimated for reference images with b > 0, which can induce an apparent time-dependence for fixed-q 0 . Restricted systems were also found to be affected. Experimentally, the exaggeration of the diffusion time-dependent effect under fixed-q 0 versus fixed-b 0 was in a range predicted theoretically, accounting for 62% (longitudinal) and 35% (radial) of the time dependence observed in white matter. Variation in the b-value of reference measurements in DW-STEAM can induce artificial diffusion time dependence in ADC, even in the absence of restriction. Magn Reson Med 79:952-959, 2018. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine.

Differential diagnosis of benign and malignant breast masses using diffusion-weighted magnetic resonance imaging.

PubMed

Min, Qinghua; Shao, Kangwei; Zhai, Lulan; Liu, Wei; Zhu, Caisong; Yuan, Lixin; Yang, Jun

2015-02-07

Diffusion-weighted magnetic resonance imaging (DW-MRI) is different from conventional diagnostic methods and has the potential to delineate the microscopic anatomy of a target tissue or organ. The purpose of our study was to evaluate the value of DW-MRI in the diagnosis of benign and malignant breast masses, which would help the clinical surgeon to decide the scope and pattern of operation. A total of 52 female patients with palpable solid breast masses received breast MRI scans using routine sequences, dynamic contrast-enhanced imaging, and diffusion-weighted echo-planar imaging at b values of 400, 600, and 800 s/mm(2), respectively. Two regions of interest (ROIs) were plotted, with a smaller ROI for the highest signal and a larger ROI for the overall lesion. Apparent diffusion coefficient (ADC) values were calculated at three different b values for all detectable lesions and from two different ROIs. The sensitivity, specificity, positive predictive value, and positive likelihood ratio of DW-MRI were determined for comparison with histological results. A total of 49 (49/52, 94.2%) lesions were detected using DW-MRI, including 20 benign lesions (two lesions detected in the same patient) and 29 malignant lesions. Benign lesion had a higher mean ADC value than their malignant counterparts, regardless of b value. According to the receiver operating characteristic (ROC) curve, the smaller-range ROI was more effective in differentiation between benign and malignant lesions. The area under the ROC curve was the largest at a b value of 800 s/mm(2). With a threshold ADC value at 1.23 × 10(-3) mm(2)/s, DW-MRI achieved a sensitivity of 82.8%, specificity of 90.0%, positive predictive value of 92.3%, and positive likelihood ratio of 8.3 for differentiating benign and malignant lesions. DW-MRI is an accurate diagnostic tool for differentiation between benign and malignant breast lesions, with an optimal b value of 800 s/mm(2). A smaller-range ROI focusing on the highest signal has a better differential value.

Malignant pleural disease: diagnosis by using diffusion-weighted and dynamic contrast-enhanced MR imaging--initial experience.

PubMed

Coolen, Johan; De Keyzer, Frederik; Nafteux, Philippe; De Wever, Walter; Dooms, Christophe; Vansteenkiste, Johan; Roebben, Ilse; Verbeken, Eric; De Leyn, Paul; Van Raemdonck, Dirk; Nackaerts, Kristiaan; Dymarkowski, Steven; Verschakelen, Johny

2012-06-01

To investigate the use of diffusion-weighted (DW) imaging for differentiating benign lesions from malignant pleural disease (MPD) and to retrospectively assess dynamic contrast material-enhanced (DCE) magnetic resonance (MR) imaging acquisitions to find out whether combining these measurements with DW imaging could improve the diagnostic value of DW imaging. This study was approved by the local ethics committee, and all patients provided written informed consent. Thirty-one consecutive patients with pleural abnormalities suspicious for MPD underwent whole-body positron emission tomography (PET)/computed tomography (CT) and thorax MR examinations. Diagnostic thoracoscopy with histopathologic analysis of pleural biopsies served as the reference standard. First-line evaluation of each suspicious lesion was performed by using the apparent diffusion coefficient (ADC) calculated from the DW image, and the optimal cutoff value was found by using receiver operating characteristic curve analysis. Afterward, DCE MR imaging data were used to improve the diagnosis in the range of ADCs where DW imaging results were equivocal. Sensitivity, specificity, and accuracy of PET/CT for diagnosis of MPD were 100%, 35.3%, and 64.5%. The optimal ADC threshold to differentiate benign lesions from MPD with DW MR imaging was 1.52 × 10(-3) mm(2)/sec, with sensitivity, specificity, and accuracy of 71.4%, 100%, and 87.1%, respectively. This result could be improved to 92.8%, 94.1%, and 93.5%, respectively, when DCE MR imaging data were included in those cases where ADC was between 1.52 and 2.00 × 10(-3) mm(2)/sec. A total of 20 patients had disease diagnosed correctly, nine had disease diagnosed incorrectly, and two cases were undetermined with PET/CT. DW imaging helped stage disease correctly in 27 patients and incorrectly in four. The undetermined cases at PET/CT were correctly diagnosed at MR imaging. DW imaging is a promising tool for differentiating MPD from benign lesions, with high accuracy, and supplementation with DCE MR imaging seems to further improve sensitivity.

Registration of T2-weighted and diffusion-weighted MR images of the prostate: comparison between manual and landmark-based methods

NASA Astrophysics Data System (ADS)

Peng, Yahui; Jiang, Yulei; Soylu, Fatma N.; Tomek, Mark; Sensakovic, William; Oto, Aytekin

2012-02-01

Quantitative analysis of multi-parametric magnetic resonance (MR) images of the prostate, including T2-weighted (T2w) and diffusion-weighted (DW) images, requires accurate image registration. We compared two registration methods between T2w and DW images. We collected pre-operative MR images of 124 prostate cancer patients (68 patients scanned with a GE scanner and 56 with Philips scanners). A landmark-based rigid registration was done based on six prostate landmarks in both T2w and DW images identified by a radiologist. Independently, a researcher manually registered the same images. A radiologist visually evaluated the registration results by using a 5-point ordinal scale of 1 (worst) to 5 (best). The Wilcoxon signed-rank test was used to determine whether the radiologist's ratings of the results of the two registration methods were significantly different. Results demonstrated that both methods were accurate: the average ratings were 4.2, 3.3, and 3.8 for GE, Philips, and all images, respectively, for the landmark-based method; and 4.6, 3.7, and 4.2, respectively, for the manual method. The manual registration results were more accurate than the landmark-based registration results (p < 0.0001 for GE, Philips, and all images). Therefore, the manual method produces more accurate registration between T2w and DW images than the landmark-based method.

Appearances of colorectal hepatic metastases at diffusion-weighted MRI compared with histopathology: initial observations.

PubMed

Scurr, E D; Collins, D J; Temple, L; Karanjia, N; Leach, M O; Koh, D-M

2012-03-01

To describe the appearances of colorectal liver metastases on diffusion-weighted MRI (DW-MRI) and to compare these appearances with histopathology. 43 patients with colorectal liver metastases were evaluated using breath-hold DW-MRI (b-values 0, 150 and 500 s mm(-2)). The b=500 s mm(-2) DW-MRI were reviewed consensually for lesion size and appearance by two readers. 18/43 patients underwent surgery allowing radiological-pathological comparison. Tissue sections were reviewed by a pathologist, who classified metastases histologically as cellular, fibrotic, necrotic or mixed. The frequency of DW-MRI findings and histological features were compared using the χ(2) test. 84 metastases were found in 43 patients. On b=500 s mm(-2) DW-MRI, metastases showed three high signal intensity patterns: rim (55/84), uniform (23/84) and variegate (6/84). Of the 55 metastases showing rim pattern, 54 were >1 cm in diameter (p<0.01, χ(2) test). 25/84 metastases were surgically resected. Of these, 11/22 metastases >1 cm in diameter showed rim pattern and demonstrated central necrosis at histopathology (p=0.04, χ(2) test). No definite relationship was found between uniform and variegate patterns with histology. Rim high signal intensity was the most common appearance of colorectal liver metastases >1 cm diameter on DW-MRI at b-values of 500 s mm(-2), a finding attributable to central necrosis.

Considerations in high resolution skeletal muscle DTI using single-shot EPI with stimulated echo preparation and SENSE

PubMed Central

Karampinos, Dimitrios C.; Banerjee, Suchandrima; King, Kevin F.; Link, Thomas M.; Majumdar, Sharmila

2011-01-01

Previous studies have shown that skeletal muscle diffusion tensor imaging (DTI) can non-invasively probe changes in the muscle fiber architecture and microstructure in diseased and damaged muscles. However, DTI fiber reconstruction in small muscles and in muscle regions close to aponeuroses and tendons remains challenging because of partial volume effects. Increasing the spatial resolution of skeletal muscle single-shot diffusion weighted (DW)-EPI can be hindered by the inherently low SNR of muscle DW-EPI due to the short muscle T2 and the high sensitivity of single-shot EPI to off-resonance effects and T2* blurring. In the present work, eddy-current compensated diffusion-weighted stimulated echo preparation is combined with sensitivity encoding (SENSE) to maintain good SNR properties and reduce the sensitivity to distortions and T2* blurring in high resolution skeletal muscle single-shot DW-EPI. An analytical framework is developed for optimizing the reduction factor and diffusion weighting time to achieve maximum SNR. Arguments for the selection of the experimental parameters are then presented considering the compromise between SNR, B0-induced distortions, T2* blurring effects and tissue incoherent motion effects. Based on the selected parameters in a high resolution skeletal muscle single-shot DW-EPI protocol, imaging protocols at lower acquisition matrix sizes are defined with matched bandwidth in the phase-encoding direction and SNR. In vivo results show that high resolution skeletal muscle DTI with minimized sensitivity to geometric distortions and T2* blurring is feasible using the proposed methodology. In particular, a significant benefit is demonstrated from reducing partial volume effects on resolving multi-pennate muscles and muscles with small cross sections in calf muscle DTI. PMID:22081519

Early detection of neuropathophysiology using diffusion-weighted magnetic resonance imaging in asymptomatic cats with feline immunodeficiency viral infection.

PubMed

Bucy, Daniel S; Brown, Mark S; Bielefeldt-Ohmann, Helle; Thompson, Jesse; Bachand, Annette M; Morges, Michelle; Elder, John H; Vandewoude, Sue; Kraft, Susan L

2011-08-01

HIV infection results in a highly prevalent syndrome of cognitive and motor disorders designated as HIV-associated dementia (HAD). Neurologic dysfunction resembling HAD has been documented in cats infected with strain PPR of the feline immunodeficiency virus (FIV), whereas another highly pathogenic strain (C36) has not been known to cause neurologic signs. Animals experimentally infected with equivalent doses of FIV-C36 or FIV-PPR, and uninfected controls were evaluated by magnetic resonance diffusion-weighted imaging (DW-MRI) and spectroscopy (MRS) at 17.5-18 weeks post-infection, as part of a study of viral clade pathogenesis in FIV-infected cats. The goals of the MR imaging portion of the project were to determine whether this methodology was capable of detecting early neuropathophysiology in the absence of outward manifestation of neurological signs and to compare the MR imaging results for the two viral strains expected to have differing degrees of neurologic effects. We hypothesized that there would be increased diffusion, evidenced by the apparent diffusion coefficient as measured by DW-MRI, and altered metabolite ratios measured by MRS, in the brains of FIV-PPR-infected cats relative to C36-infected cats and uninfected controls. Increased apparent diffusion coefficients were seen in the white matter, gray matter, and basal ganglia of both the PPR and C36-infected (asymptomatic) cats. Thalamic MRS metabolite ratios did not differ between groups. The equivalently increased diffusion by DW-MRI suggests similar indirect neurotoxicity mechanisms for the two viral genotypes. DW-MRI is a sensitive tool to detect neuropathophysiological changes in vivo that could be useful during longitudinal studies of FIV.

Identification of residual breast carcinoma following neoadjuvant chemotherapy: diffusion-weighted imaging--comparison with contrast-enhanced MR imaging and pathologic findings.

PubMed

Woodhams, Reiko; Kakita, Satoko; Hata, Hirofumi; Iwabuchi, Keiichi; Kuranami, Masaru; Gautam, Shiva; Hatabu, Hiroto; Kan, Shinichi; Mountford, Carolyn

2010-02-01

To compare the capability of diffusion-weighted (DW) and contrast material-enhanced magnetic resonance (MR) imaging to provide diagnostic information on residual breast cancers following neoadjuvant chemotherapy and to assess apparent diffusion coefficients (ADCs) of the carcinoma prior to neoadjuvant chemotherapy to determine if the method could help predict response to chemotherapy. Institutional review board approval and informed consent were obtained. Three hundred ninety-eight patients underwent MR imaging of the breast, including DW MR (b values, 0 and 1500 sec/mm(2)) and contrast-enhanced MR imaging. Of these, the contralateral breast in 73 women was used as a control. Seventy-two patients with 73 lesions with malignant disease were treated by using neoadjuvant chemotherapy and were examined for residual disease following therapy. Three were excluded because of prolonged intervals between final MR imaging and surgery. Thus, 69 patients (70 lesions) with DW and contrast-enhanced MR imaging results were compared with postoperative histopathologic findings. The ADCs of the carcinoma prior to neoadjuvant chemotherapy were calculated for each patient, and those with complete response and residual disease were compared. The accuracy for depicting residual tumor was 96% for DW MR imaging, compared with an accuracy of 89% for contrast-enhanced MR imaging (P = .06). There was no significant difference in prechemotherapy ADCs between pathologic complete response cases and those with residual disease. DW MR imaging had at least as good of accuracy as did contrast-enhanced MR imaging for monitoring neoadjuvant chemotherapy. The ADCs prior to chemotherapy did not predict response to chemotherapy. The use of DW imaging to visualize residual breast cancer without the need for contrast medium could be advantageous in women with impaired renal function. (c) RSNA, 2010

Diffusion MRI in early cancer therapeutic response assessment

PubMed Central

Galbán, C. J.; Hoff, B. A.; Chenevert, T. L.; Ross, B. D.

2016-01-01

Imaging biomarkers for the predictive assessment of treatment response in patients with cancer earlier than standard tumor volumetric metrics would provide new opportunities to individualize therapy. Diffusion-weighted MRI (DW-MRI), highly sensitive to microenvironmental alterations at the cellular level, has been evaluated extensively as a technique for the generation of quantitative and early imaging biomarkers of therapeutic response and clinical outcome. First demonstrated in a rodent tumor model, subsequent studies have shown that DW-MRI can be applied to many different solid tumors for the detection of changes in cellularity as measured indirectly by an increase in the apparent diffusion coefficient (ADC) of water molecules within the lesion. The introduction of quantitative DW-MRI into the treatment management of patients with cancer may aid physicians to individualize therapy, thereby minimizing unnecessary systemic toxicity associated with ineffective therapies, saving valuable time, reducing patient care costs and ultimately improving clinical outcome. This review covers the theoretical basis behind the application of DW-MRI to monitor therapeutic response in cancer, the analytical techniques used and the results obtained from various clinical studies that have demonstrated the efficacy of DW-MRI for the prediction of cancer treatment response. PMID:26773848

Isotropic non-white matter partial volume effects in constrained spherical deconvolution.

PubMed

Roine, Timo; Jeurissen, Ben; Perrone, Daniele; Aelterman, Jan; Leemans, Alexander; Philips, Wilfried; Sijbers, Jan

2014-01-01

Diffusion-weighted (DW) magnetic resonance imaging (MRI) is a non-invasive imaging method, which can be used to investigate neural tracts in the white matter (WM) of the brain. Significant partial volume effects (PVEs) are present in the DW signal due to relatively large voxel sizes. These PVEs can be caused by both non-WM tissue, such as gray matter (GM) and cerebrospinal fluid (CSF), and by multiple non-parallel WM fiber populations. High angular resolution diffusion imaging (HARDI) methods have been developed to correctly characterize complex WM fiber configurations, but to date, many of the HARDI methods do not account for non-WM PVEs. In this work, we investigated the isotropic PVEs caused by non-WM tissue in WM voxels on fiber orientations extracted with constrained spherical deconvolution (CSD). Experiments were performed on simulated and real DW-MRI data. In particular, simulations were performed to demonstrate the effects of varying the diffusion weightings, signal-to-noise ratios (SNRs), fiber configurations, and tissue fractions. Our results show that the presence of non-WM tissue signal causes a decrease in the precision of the detected fiber orientations and an increase in the detection of false peaks in CSD. We estimated 35-50% of WM voxels to be affected by non-WM PVEs. For HARDI sequences, which typically have a relatively high degree of diffusion weighting, these adverse effects are most pronounced in voxels with GM PVEs. The non-WM PVEs become severe with 50% GM volume for maximum spherical harmonics orders of 8 and below, and already with 25% GM volume for higher orders. In addition, a low diffusion weighting or SNR increases the effects. The non-WM PVEs may cause problems in connectomics, where reliable fiber tracking at the WM-GM interface is especially important. We suggest acquiring data with high diffusion-weighting 2500-3000 s/mm(2), reasonable SNR (~30) and using lower SH orders in GM contaminated regions to minimize the non-WM PVEs in CSD.

Diffusion-weighted magnetic resonance imaging for assessment of lung lesions: repeatability of the apparent diffusion coefficient measurement.

PubMed

Bernardin, L; Douglas, N H M; Collins, D J; Giles, S L; O'Flynn, E A M; Orton, M; deSouza, N M

2014-02-01

To establish repeatability of apparent diffusion coefficients (ADCs) acquired from free-breathing diffusion-weighted magnetic resonance imaging (DW-MRI) in malignant lung lesions and investigate effects of lesion size, location and respiratory motion. Thirty-six malignant lung lesions (eight patients) were examined twice (1- to 5-h interval) using T1-weighted, T2-weighted and axial single-shot echo-planar DW-MRI (b = 100, 500, 800 s/mm(2)) during free-breathing. Regions of interest around target lesions on computed b = 800 s/mm(2) images by two independent observers yielded ADC values from maps (pixel-by-pixel fitting using all b values and a mono-exponential decay model). Intra- and inter-observer repeatability was assessed per lesion, per patient and by lesion size (> or <2 cm) or location. ADCs were similar between observers (mean ± SD, 1.15 ± 0.28 × 10(-3) mm(2)/s, observer 1; 1.15 ± 0.29 × 10(-3) mm(2)/s, observer 2). Intra-observer coefficients of variation of the mean [median] ADC per lesion and per patient were 11% [11.4%], 5.7% [5.7%] for observer 1 and 9.2% [9.5%], 3.9% [4.7%] for observer 2 respectively; inter-observer values were 8.9% [9.3%] (per lesion) and 3.0% [3.7%] (per patient). Inter-observer coefficient of variation (CoV) was greater for lesions <2 cm (n = 20) compared with >2 cm (n = 16) (10.8% vs 6.5% ADCmean, 11.3% vs 6.7% ADCmedian) and for mid (n = 14) vs apical (n = 9) or lower zone (n = 13) lesions (13.9%, 2.7%, 3.8% respectively ADCmean; 14.2%, 2.8%, 4.7% respectively ADCmedian). Free-breathing DW-MRI of whole lung achieves good intra- and inter-observer repeatability of ADC measurements in malignant lung tumours. • Diffusion-weighted MRI of the lung can be satisfactorily acquired during free-breathing • DW-MRI demonstrates high contrast between primary and metastatic lesions and normal lung • Apparent diffusion coefficient (ADC) measurements in lung tumours are repeatable and reliable • ADC offers potential in assessing response in lung metastases in clinical trials.

Considerations in high-resolution skeletal muscle diffusion tensor imaging using single-shot echo planar imaging with stimulated-echo preparation and sensitivity encoding.

PubMed

Karampinos, Dimitrios C; Banerjee, Suchandrima; King, Kevin F; Link, Thomas M; Majumdar, Sharmila

2012-05-01

Previous studies have shown that skeletal muscle diffusion tensor imaging (DTI) can noninvasively probe changes in the muscle fiber architecture and microstructure in diseased and damaged muscles. However, DTI fiber reconstruction in small muscles and in muscle regions close to aponeuroses and tendons remains challenging because of partial volume effects. Increasing the spatial resolution of skeletal muscle single-shot diffusion-weighted echo planar imaging (DW-EPI) can be hindered by the inherently low signal-to-noise ratio (SNR) of muscle DW-EPI because of the short muscle T(2) and the high sensitivity of single-shot EPI to off-resonance effects and T(2)* blurring. In this article, eddy current-compensated diffusion-weighted stimulated-echo preparation is combined with sensitivity encoding (SENSE) to maintain good SNR properties and to reduce the sensitivity to distortions and T(2)* blurring in high-resolution skeletal muscle single-shot DW-EPI. An analytical framework is developed to optimize the reduction factor and diffusion weighting time to achieve maximum SNR. Arguments for the selection of the experimental parameters are then presented considering the compromise between SNR, B(0)-induced distortions, T(2)* blurring effects and tissue incoherent motion effects. On the basis of the selected parameters in a high-resolution skeletal muscle single-shot DW-EPI protocol, imaging protocols at lower acquisition matrix sizes are defined with matched bandwidth in the phase-encoding direction and SNR. In  vivo results show that high-resolution skeletal muscle DTI with minimized sensitivity to geometric distortions and T(2)* blurring is feasible using the proposed methodology. In particular, a significant benefit is demonstrated from a reduction in partial volume effects for resolving multi-pennate muscles and muscles with small cross-sections in calf muscle DTI. Copyright © 2011 John Wiley & Sons, Ltd.

Appearances of colorectal hepatic metastases at diffusion-weighted MRI compared with histopathology: initial observations

PubMed Central

Scurr, E D; Collins, D J; Temple, L; Karanjia, N; Leach, M O; Koh, D-M

2012-01-01

Objective To describe the appearances of colorectal liver metastases on diffusion-weighted MRI (DW-MRI) and to compare these appearances with histopathology. Methods 43 patients with colorectal liver metastases were evaluated using breath-hold DW-MRI (b-values 0, 150 and 500 s mm–2). The b=500 s mm–2 DW-MRI were reviewed consensually for lesion size and appearance by two readers. 18/43 patients underwent surgery allowing radiological–pathological comparison. Tissue sections were reviewed by a pathologist, who classified metastases histologically as cellular, fibrotic, necrotic or mixed. The frequency of DW-MRI findings and histological features were compared using the χ2 test. Results 84 metastases were found in 43 patients. On b=500 s mm–2 DW-MRI, metastases showed three high signal intensity patterns: rim (55/84), uniform (23/84) and variegate (6/84). Of the 55 metastases showing rim pattern, 54 were >1 cm in diameter (p<0.01, χ2 test). 25/84 metastases were surgically resected. Of these, 11/22 metastases >1 cm in diameter showed rim pattern and demonstrated central necrosis at histopathology (p=0.04, χ2 test). No definite relationship was found between uniform and variegate patterns with histology. Conclusion Rim high signal intensity was the most common appearance of colorectal liver metastases >1 cm diameter on DW-MRI at b-values of 500 s mm–2, a finding attributable to central necrosis. PMID:21224302

The Role of Diffusion-Weighted Magnetic Resonance Imaging in the Differentiation of Head and Neck Masses.

PubMed

Kanmaz, Lutfi; Karavas, Erdal

2018-05-29

The purpose of this study was to evaluate the value of diffusion-weighted MRI (DW-MRI) in differentiating benign and malignant head and neck masses by comparing their apparent diffusion coefficient (ADC) values. The study included 32 patients with a neck mass >1 cm in diameter who were examined with echo planar DW-MRI. Two different diffusion gradients (b values of b = 0 and b = 1000 s/mm²) were applied. DWI and ADC maps of 32 neck masses in 32 patients were obtained. Mean ADC values of benign and malignant neck lesions were measured and compared statistically. A total of 15 (46.9%) malignant masses and 17 (53.1%) benign masses were determined. Of all the neck masses, the ADC value of cystic masses was the highest and that of lymphomas was the lowest. The mean ADC values of benign and malignant neck masses were 1.57 × 10 -3 mm²/s and 0.90 × 10 -3 mm²/s, respectively. The difference between mean ADC values of benign and malignant neck masses was significant ( p < 0.01). Diffusion-weighted MRI with ADC measurements can be useful in the differential diagnosis of neck masses.

Diffusion-Weighted Magnetic Resonance Imaging to Evaluate Major Salivary Gland Function Before and After Radiotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dirix, Piet; Keyzer, Frederik de; Vandecaveye, Vincent

2008-08-01

Purpose: To evaluate diffusion-weighted (DW)-MRI as a noninvasive tool to investigate major salivary gland function before and after radiotherapy (RT) for head and neck cancer (HNC). Methods and Materials: DW-MRI was performed in 8 HNC patients before and after parotid-sparing RT (mean dose to the contralateral parotid gland <26 Gy). A DW sequence was performed once at rest and then repeated continuously during salivary stimulation. Apparent diffusion coefficient (ADC) maps for both parotid and submandibular glands were calculated. Findings were compared with salivary gland scintigraphy. Results: Before RT, the mean ADC value at rest was significantly lower in the parotidmore » than in the submandibular glands. During the first 5 min of stimulation, the ADC value of the salivary glands showed a decrease, followed by a steady increase until a peak ADC, significantly higher than the baseline value, was reached after a median of 17 min. The baseline ADC value at rest was significantly higher after RT than before RT in the nonspared salivary glands but not in the spared parotid glands. In the contralateral parotid glands, the same response was seen as before RT. This pattern was completely lost in the nonspared glands. These results corresponded with remaining or loss of salivary function, respectively, as confirmed by salivary gland scintigraphy. Conclusions: Diffusion-weighted-MRI allows noninvasive evaluation of functional changes in the major salivary glands after RT and is a promising tool for investigating radiation-induced xerostomia.« less

Spurious group differences due to head motion in a diffusion MRI study

PubMed Central

Yendiki, Anastasia; Koldewyn, Kami; Kakunoori, Sita; Kanwisher, Nancy; Fischl, Bruce

2014-01-01

Diffusion-weighted MRI (DW-MRI) has become a popular imaging modality for probing the microstructural properties of white matter and comparing them between populations in vivo. However, the contrast in DW-MRI arises from the microscopic random motion of water molecules in brain tissues, which makes it particularly sensitive to macroscopic head motion. Although this has been known since the introduction of DW-MRI, most studies that use this modality for group comparisons do not report measures of head motion for each group and rely on registration-based correction methods that cannot eliminate the full effects of head motion on the DW-MRI contrast. In this work we use data from children with autism and typically developing children to investigate the effects of head motion on differences in anisotropy and diffusivity measures between groups. We show that group differences in head motion can induce group differences in DW-MRI measures, and that this is the case even when comparing groups that include control subjects only, where no anisotropy or diffusivity differences are expected. We also show that such effects can be more prominent in some white-matter pathways than others, and that they can be ameliorated by including motion as a nuisance regressor in the analyses. Our results demonstrate the importance of taking head motion into account in any population study where one group might exhibit more head motion than the other. PMID:24269273

Intrahepatic and hilar mass-forming cholangiocarcinoma: Qualitative and quantitative evaluation with diffusion-weighted MR imaging.

PubMed

Fattach, Hassan El; Dohan, Anthony; Guerrache, Youcef; Dautry, Raphael; Boudiaf, Mourad; Hoeffel, Christine; Soyer, Philippe

2015-08-01

To qualitatively and quantitatively analyze the presentation of intrahepatic and hilar mass-forming cholangiocarcinoma with diffusion-weighted magnetic resonance imaging (DW-MRI). Twenty-eight patients with histopathologically proven mass-forming cholangiocarcinoma (hilar, n=17; intrahepatic, n=11) underwent hepatic DW-MRI at 1.5-T using free-breathing acquisition and three b-values (0,400,800s/mm(2)). Cholangiocarcinomas were evaluated qualitatively using visual analysis of DW-MR images and quantitatively with conventional ADC and normalized ADC measurements using liver and spleen as reference organs. All cholangiocarcinomas (28/28; 100%) were visible on DW-MR images. DW-MRI yielded best conspicuity of cholangiocarcinomas than the other MRI sequences (P<0.001). Seven cholangiocarcinomas (7/11; 64%) showed hypointense central area on DW-MR images. Conventional ADC value of cholangiocarcinomas (1.042×10(-3)mm(2)/s±0.221×10(-3)mm(2)/s; range: 0.616×10(-3)mm(2)/s to 2.050×10(-3)mm(2)/s) was significantly lower than that of apparently normal hepatic parenchyma (1.362×10(-3)mm(2)/s±0.187×10(-3)mm(2)/s) (P<0.0001), although substantial overlap was found. No significant differences in ADC and normalized ADC values were found between intrahepatic and hilar cholangiocarcinomas. The use of normalized ADC using the liver as reference organ resulted in the most restricted distribution of ADC values of cholangiocarcinomas (variation coefficient=16.6%). There is a trend towards a common appearance of intrahepatic and hilar mass-forming cholangiocarcinomas on DW-MRI but variations may be observed. Familiarity with these variations may improve the diagnosis of mass-forming cholangiocarcinoma. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Unilateral or bilateral punctate hippocampal hyperintensities on DW-MRI: seizures, amnesia, or both?

PubMed

Bocos-Portillo, Jone; Escalza-Cortina, Inés; Gómez-Beldarrain, Marian; Rodriguez-Sainz, Aida; Garcia-Monco, Juan Carlos

2018-06-02

The presence of small hippocampal hyperintense lesions on diffusion-weighted (DW) MRI can respond to different etiologies and represents a challenge where clinical judgment is imperative, since therapeutic approach may be quite different.We here report three patients with similar neuroradiological findings, i.e., hyperintense punctate hippocampal lesions on diffusion-weighted MRI sequences, yet of different origin. The first one presented with isolated amnesia (transient global amnesia), the second one with amnesia and seizures, and the third one with seizures.Thus, hippocampal punctate lesions appear after transient global amnesia, but the same pattern may be present after seizures, either focal-onset or generalized seizures. This peculiar radiological MRI pattern could indicate a pathogenic link between transient global amnesia (TGA) and seizures which should be further studied.

ADC Quantification of the Vertebral Bone Marrow Water Component: Removing the Confounding Effect of Residual Fat.

PubMed

Dieckmeyer, Michael; Ruschke, Stefan; Eggers, Holger; Kooijman, Hendrik; Rummeny, Ernst J; Kirschke, Jan S; Baum, Thomas; Karampinos, Dimitrios C

2017-10-01

To remove the confounding effect of unsuppressed fat on the imaging-based apparent diffusion coefficient (ADC) of the vertebral bone marrow water component when using spectrally selective fat suppression and to compare and validate the proposed quantification strategy against diffusion-weighted magnetic resonance spectroscopy (DW-MRS). Twelve subjects underwent diffusion-weighted imaging (DWI) and DW-MRS of the vertebral bone marrow. A theoretical model was developed to take into account and correct the effects of residual fat on ADC, incorporating additional measurements for proton density fat fraction (PDFF) and water T 2 (T 2w ). Uncorrected and corrected DWI-based ADC was compared with DW-MRS-based ADC using the Bland-Altman method. There was a systematic bias equal to 0.118 ± 0.116 × 10 -3 mm 2 /s between DWI and DW-MRS when no correction was performed. Taking into account measured PDFF and constant T 2w reduced the bias to 0.006 ± 0.128 × 10 -3 mm 2 /s. Using the proposed approach with both individually measured PDFF and T 2w reduced both the bias and the limits of agreement between DWI and DW-MRS (0.018 ± 0.065 × 10 -3 mm 2 /s). By taking into account the presence of residual fat in a modified signal model that incorporates additional individual measurements of PDFF and T 2w , good agreement of imaging-based ADC with MRS-based ADC can be achieved in vertebral bone marrow. Magn Reson Med 78:1432-1441, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

Multi-institutional validation of a novel textural analysis tool for preoperative stratification of suspected thyroid tumors on diffusion-weighted MRI.

PubMed

Brown, Anna M; Nagala, Sidhartha; McLean, Mary A; Lu, Yonggang; Scoffings, Daniel; Apte, Aditya; Gonen, Mithat; Stambuk, Hilda E; Shaha, Ashok R; Tuttle, R Michael; Deasy, Joseph O; Priest, Andrew N; Jani, Piyush; Shukla-Dave, Amita; Griffiths, John

2016-04-01

Ultrasound-guided fine needle aspirate cytology fails to diagnose many malignant thyroid nodules; consequently, patients may undergo diagnostic lobectomy. This study assessed whether textural analysis (TA) could noninvasively stratify thyroid nodules accurately using diffusion-weighted MRI (DW-MRI). This multi-institutional study examined 3T DW-MRI images obtained with spin echo echo planar imaging sequences. The training data set included 26 patients from Cambridge, United Kingdom, and the test data set included 18 thyroid cancer patients from Memorial Sloan Kettering Cancer Center (New York, New York, USA). Apparent diffusion coefficients (ADCs) were compared over regions of interest (ROIs) defined on thyroid nodules. TA, linear discriminant analysis (LDA), and feature reduction were performed using the 21 MaZda-generated texture parameters that best distinguished benign and malignant ROIs. Training data set mean ADC values were significantly different for benign and malignant nodules (P = 0.02) with a sensitivity and specificity of 70% and 63%, respectively, and a receiver operator characteristic (ROC) area under the curve (AUC) of 0.73. The LDA model of the top 21 textural features correctly classified 89/94 DW-MRI ROIs with 92% sensitivity, 96% specificity, and an AUC of 0.97. This algorithm correctly classified 16/18 (89%) patients in the independently obtained test set of thyroid DW-MRI scans. TA classifies thyroid nodules with high sensitivity and specificity on multi-institutional DW-MRI data sets. This method requires further validation in a larger prospective study. Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance. © 2015 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine.

PSF mapping-based correction of eddy-current-induced distortions in diffusion-weighted echo-planar imaging.

PubMed

In, Myung-Ho; Posnansky, Oleg; Speck, Oliver

2016-05-01

To accurately correct diffusion-encoding direction-dependent eddy-current-induced geometric distortions in diffusion-weighted echo-planar imaging (DW-EPI) and to minimize the calibration time at 7 Tesla (T). A point spread function (PSF) mapping based eddy-current calibration method is newly presented to determine eddy-current-induced geometric distortions even including nonlinear eddy-current effects within the readout acquisition window. To evaluate the temporal stability of eddy-current maps, calibration was performed four times within 3 months. Furthermore, spatial variations of measured eddy-current maps versus their linear superposition were investigated to enable correction in DW-EPIs with arbitrary diffusion directions without direct calibration. For comparison, an image-based eddy-current correction method was additionally applied. Finally, this method was combined with a PSF-based susceptibility-induced distortion correction approach proposed previously to correct both susceptibility and eddy-current-induced distortions in DW-EPIs. Very fast eddy-current calibration in a three-dimensional volume is possible with the proposed method. The measured eddy-current maps are very stable over time and very similar maps can be obtained by linear superposition of principal-axes eddy-current maps. High resolution in vivo brain results demonstrate that the proposed method allows more efficient eddy-current correction than the image-based method. The combination of both PSF-based approaches allows distortion-free images, which permit reliable analysis in diffusion tensor imaging applications at 7T. © 2015 Wiley Periodicals, Inc.

Diffusion-weighted magnetic resonance imaging and apparent diffusion coefficient mapping for diagnosing infectious spondylodiscitis: a preliminary study.

PubMed

Chen, Tai-Yuan; Wu, Te-Chang; Tsui, Yu-Kun; Chen, Hou-Hsun; Lin, Chien-Jen; Lee, Huey-Jen; Wu, Tai-Ching

2015-01-01

Though diffusion-weighted (DW) magnetic resonance imaging (MRI) is useful for diagnosing many pathologies, its use in infectious spondylodiscitis is unclear. We aimed to evaluate the use of DW MRI and apparent diffusion coefficient (ADC) mapping for the diagnosis of infectious spondylodiscitis. In this retrospective study, 17 patients with confirmed infectious spondylodiscitis were matched by age and level of infected disc with 17 patients with degenerative disc disease (DDD) and 17 healthy controls. All patients received conventional MRI and diffusion-weighted imaging (DWI) in the same imaging session. ADC values of the 3 groups of patients were compared. The mean age of each group was 67.4 ± 11.6 years. The mean ADCs of the normal control, DDD, and infectious spondylodiscitis groups were 1.76 ± 0.19 × 10(-3) , 1.12 ± 0.22 × 10(-3) , and 1.27 ± 0.38 × 10(-3) mm2 /second, respectively. The ADCs of the DDD and infectious spondylodiscitis groups were both significantly lower than that of the normal control group (both, P < 0.001). These data suggest that DWI/ADC MRI may be useful in the early diagnosis of infectious spondylodiscitis. © 2014 The Authors. Journal of Neuroimaging published by Wiley Periodicals, Inc. on behalf of American Society of Neuroimaging.

Task-based evaluation of segmentation algorithms for diffusion-weighted MRI without using a gold standard

PubMed Central

Jha, Abhinav K.; Kupinski, Matthew A.; Rodríguez, Jeffrey J.; Stephen, Renu M.; Stopeck, Alison T.

2012-01-01

In many studies, the estimation of the apparent diffusion coefficient (ADC) of lesions in visceral organs in diffusion-weighted (DW) magnetic resonance images requires an accurate lesion-segmentation algorithm. To evaluate these lesion-segmentation algorithms, region-overlap measures are used currently. However, the end task from the DW images is accurate ADC estimation, and the region-overlap measures do not evaluate the segmentation algorithms on this task. Moreover, these measures rely on the existence of gold-standard segmentation of the lesion, which is typically unavailable. In this paper, we study the problem of task-based evaluation of segmentation algorithms in DW imaging in the absence of a gold standard. We first show that using manual segmentations instead of gold-standard segmentations for this task-based evaluation is unreliable. We then propose a method to compare the segmentation algorithms that does not require gold-standard or manual segmentation results. The no-gold-standard method estimates the bias and the variance of the error between the true ADC values and the ADC values estimated using the automated segmentation algorithm. The method can be used to rank the segmentation algorithms on the basis of both accuracy and precision. We also propose consistency checks for this evaluation technique. PMID:22713231

Whole-body diffusion-weighted MR image stitching and alignment to anatomical MRI

NASA Astrophysics Data System (ADS)

Ceranka, Jakub; Polfliet, Mathias; Lecouvet, Frederic; Michoux, Nicolas; Vandemeulebroucke, Jef

2017-02-01

Whole-body diffusion-weighted (WB-DW) MRI in combination with anatomical MRI has shown a great poten- tial in bone and soft tissue tumour detection, evaluation of lymph nodes and treatment response assessment. Because of the vast body coverage, whole-body MRI is acquired in separate stations, which are subsequently combined into a whole-body image. However, inter-station and inter-modality image misalignments can occur due to image distortions and patient motion during acquisition, which may lead to inaccurate representations of patient anatomy and hinder visual assessment. Automated and accurate whole-body image formation and alignment of the multi-modal MRI images is therefore crucial. We investigated several registration approaches for the formation or stitching of the whole-body image stations, followed by a deformable alignment of the multi- modal whole-body images. We compared a pairwise approach, where diffusion-weighted (DW) image stations were sequentially aligned to a reference station (pelvis), to a groupwise approach, where all stations were simultaneously mapped to a common reference space while minimizing the overall transformation. For each, a choice of input images and corresponding metrics was investigated. Performance was evaluated by assessing the quality of the obtained whole-body images, and by verifying the accuracy of the alignment with whole-body anatomical sequences. The groupwise registration approach provided the best compromise between the formation of WB- DW images and multi-modal alignment. The fully automated method was found to be robust, making its use in the clinic feasible.

Improved differentiation between hepatic hemangioma and metastases on diffusion-weighted MRI by measurement of standard deviation of apparent diffusion coefficient.

PubMed

Hardie, Andrew D; Egbert, Robert E; Rissing, Michael S

2015-01-01

Diffusion-weighted magnetic resonance imaging (DW-MR) can be useful in the differentiation of hemangiomata from liver metastasis, but improved methods other than by mean apparent diffusion coefficient (mADC) are needed. A retrospective review identified 109 metastatic liver lesions and 86 hemangiomata in 128 patients who had undergone DW-MR. For each lesion, mADC and the standard deviation of the mean ADC (sdADC) were recorded and compared by receiver operating characteristic analysis. Mean mADC was higher in benign hemangiomata (1.52±0.12 mm(2)/s) than in liver metastases (1.33±0.18 mm(2)/s), but there was significant overlap in values. The mean sdADC was lower in hemangiomata (101±17 mm(2)/s) than metastases (245±25 mm(2)/s) and demonstrated no overlap in values, which was significantly different (P<.0001). Hemangiomata may be better able to be differentiated from liver metastases on the basis of sdADC than by mADC, although further studies are needed. Copyright © 2015 Elsevier Inc. All rights reserved.

Improved Performance in Differentiating Benign from Malignant Sinonasal Tumors Using Diffusion-weighted Combined with Dynamic Contrast-enhanced Magnetic Resonance Imaging

PubMed Central

Wang, Xin-Yan; Yan, Fei; Hao, Hui; Wu, Jian-Xing; Chen, Qing-Hua; Xian, Jun-Fang

2015-01-01

Background: Differentiating benign from malignant sinonsal lesions is essential for treatment planning as well as determining the patient's prognosis, but the differentiation is often difficult in clinical practice. The study aimed to determine whether the combination of diffusion-weighted (DW) and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) can improve the performance in differentiating benign from malignant sinonasal tumors. Methods: This retrospective study included 197 consecutive patients with sinonasal tumors (116 malignant tumors and 81 benign tumors). All patients underwent both DW and DCE-MRI in a 3-T magnetic resonance scanner. Two different settings of b values (0,700 and 0,1000 s/mm2) and two different strategies of region of interest (ROI) including whole slice (WS) and partial slice (PS) were used to calculate apparent diffusion coefficients (ADCs). A DW parameter with WS ADCsb0,1000 and two DCE-MRI parameters (time intensity curve [TIC] and time to peak enhancement [Tpeak]) were finally combined to use in differentiating the benign from the malignant tumors in this study. Results: The mean ADCs of malignant sinonasal tumors (WS ADCsb0,1000 = 1.084 × 10−3 mm2/s) were significantly lower than those of benign tumors (WS ADCsb0,1000 = 1.617 × 10−3 mm2/s, P < 0.001). The accuracy using WS ADCsb0,1000 alone was 83.7% in differentiating the benign from the malignant tumors (85.3% sensitivity, 81.2% specificity, 86.4% positive predictive value [PPV], and 79.5% negative predictive value [NPV]). The accuracy using DCE with Tpeak and TIC alone was 72.1% (69.1% sensitivity, 74.1% specificity, 77.5% PPV, and 65.1% NPV). Using DW-MRI parameter was superior than using DCE parameters in differentiation between benign and malignant sinonasal tumors (P < 0.001). The accuracy was 87.3% (90.5% sensitivity, 82.7% specificity, 88.2% PPV, and 85.9% NPV) using DW-MRI combined with DCE-MRI, which was superior than that using DCE-MRI alone or using DW-MRI alone (both P < 0.001) in differentiating the benign from the malignant tumors. Conclusions: Diffusion-weighted combined with DCE-MRI can improve imaging performance in differentiating benign from malignant sinonasal tumors, which has the potential to improve diagnostic accuracy and to provide added value in the management for these tumors. PMID:25698188

Detection of cancer in cervical tissue biopsies using mobile lipid resonances measured with diffusion-weighted (1)H magnetic resonance spectroscopy.

PubMed

Zietkowski, D; Davidson, R L; Eykyn, T R; De Silva, S S; Desouza, N M; Payne, G S

2010-05-01

The purpose of this study was to implement a diffusion-weighted sequence for visualisation of mobile lipid resonances (MLR) using high resolution magic angle spinning (HR-MAS) (1)H MRS and to evaluate its use in establishing differences between tissues from patients with cervical carcinoma that contain cancer from those that do not. A stimulated echo sequence with bipolar gradients was modified to allow T(1) and T(2) measurements and optimised by recording signal loss in HR-MAS spectra as a function of gradient strength in model lipids and tissues. Diffusion coefficients, T(1) and apparent T(2) relaxation times were measured in model lipid systems. MLR profiles were characterised in relation to T(1) and apparent T(2) relaxation in human cervical cancer tissue samples. Diffusion-weighted (DW) spectra of cervical biopsies were quantified and peak areas analysed using linear discriminant analysis (LDA). The optimised sequence reduced spectral overlap by suppressing signals originating from low molecular weight metabolites and non-lipid contributions. Significantly improved MLR visualisation allowed visualisation of peaks at 0.9, 1.3, 1.6, 2.0, 2.3, 2.8, 4.3 and 5.3 ppm. MLR analysis of DW spectra showed at least six peaks arising from saturated and unsaturated lipids and those arising from triglycerides. Significant differences in samples containing histologically confirmed cancer were seen for peaks at 0.9 (p < 0.006), 1.3 (p < 0.04), 2.0 (p < 0.03), 2.8 (p < 0.003) and 4.3 ppm (p < 0.0002). LDA analysis of MLR peaks from DW spectra almost completely separated two clusters of cervical biopsies (cancer, 'no-cancer'), reflecting underlying differences in MLR composition. Generated Receiver Operating Characteristic (ROC) curves and calculated area under the curve (0.962) validated high sensitivity and specificity of the technique. Diffusion-weighting of HR-MAS spectroscopic sequences is a useful method for characterising MLR in cancer tissues and displays an accumulation of lipids arising during tumourigenesis and an increase in the unsaturated lipid and triglyceride peaks with respect to saturated MLR. Copyright © 2009 John Wiley & Sons, Ltd.

Diffusion-prepared stimulated-echo turbo spin echo (DPsti-TSE): An eddy current-insensitive sequence for three-dimensional high-resolution and undistorted diffusion-weighted imaging.

PubMed

Zhang, Qinwei; Coolen, Bram F; Versluis, Maarten J; Strijkers, Gustav J; Nederveen, Aart J

2017-07-01

In this study, we present a new three-dimensional (3D), diffusion-prepared turbo spin echo sequence based on a stimulated-echo read-out (DPsti-TSE) enabling high-resolution and undistorted diffusion-weighted imaging (DWI). A dephasing gradient in the diffusion preparation module and rephasing gradients in the turbo spin echo module create stimulated echoes, which prevent signal loss caused by eddy currents. Near to perfect agreement of apparent diffusion coefficient (ADC) values between DPsti-TSE and diffusion-weighted echo planar imaging (DW-EPI) was demonstrated in both phantom transient signal experiments and phantom imaging experiments. High-resolution and undistorted DPsti-TSE was demonstrated in vivo in prostate and carotid vessel wall. 3D whole-prostate DWI was achieved with four b values in only 6 min. Undistorted ADC maps of the prostate peripheral zone were obtained at low and high imaging resolutions with no change in mean ADC values [(1.60 ± 0.10) × 10 -3 versus (1.60 ± 0.02) × 10 -3  mm 2 /s]. High-resolution 3D DWI of the carotid vessel wall was achieved in 12 min, with consistent ADC values [(1.40 ± 0.23) × 10 -3  mm 2 /s] across different subjects, as well as slice locations through the imaging volume. This study shows that DPsti-TSE can serve as a robust 3D diffusion-weighted sequence and is an attractive alternative to the traditional two-dimensional DW-EPI approaches. Copyright © 2017 John Wiley & Sons, Ltd.

Improvement of Hyperemic Myocardial Oxygen Extraction Fraction Estimation By A Diffusion Prepared Sequence

PubMed Central

McCommis, Kyle S.; Koktzoglou, Ioannis; Zhang, Haosen; Goldstein, Thomas A.; Northrup, Benjamin E.; Li, Debiao; Gropler, Robert J.; Zheng, Jie

2010-01-01

Myocardial oxygen extraction fraction (OEF) during hyperemia can be estimated using a double-inversion-recovery (DIR) prepared T2-weighted black-blood sequence. Severe irregular ECG-triggering due to elevated heart rate and/or arrhythmias may render it difficult to adequately suppress the flowing left ventricle blood signal and thus potentially cause errors in the estimates of myocardial OEF. Thus, the goal of this study was to evaluate another black-blood technique, a diffusion-weighted (DW)-prepared TSE sequence for its ability to determine regional myocardial OEF during hyperemia. Control dogs and dogs with acute coronary artery stenosis were imaged with both the DIR- and DW-prepared TSE sequences at rest and during either dipyridamole or dobutamine hyperemia. Validation of MRI OEF estimates was performed using blood sampling from the artery and coronary sinus in control dogs. The two methods showed comparable correlations with blood sampling results (R2 = 0.9). Similar OEF estimations for all dogs were observed except for the group of dogs with severe coronary stenosis during dobutamine stress. In these dogs, the DW method provided more physiologically reasonable OEF (hyperemic OEF = 0.75 ± 0.08 vs resting OEF of 0.6) than the DIR method (hyperemic OEF = 0.56 ± 0.10). DW-preparation may be a valuable alternative for more accurate oxygenation measurements during irregular ECG-triggering. PMID:20512871

Optimization of diffusion-weighted single-refocused spin-echo EPI by reducing eddy-current artifacts and shortening the echo time.

PubMed

Shrestha, Manoj; Hok, Pavel; Nöth, Ulrike; Lienerth, Bianca; Deichmann, Ralf

2018-03-30

The purpose of this work was to optimize the acquisition of diffusion-weighted (DW) single-refocused spin-echo (srSE) data without intrinsic eddy-current compensation (ECC) for an improved performance of ECC postprocessing. The rationale is that srSE sequences without ECC may yield shorter echo times (TE) and thus higher signal-to-noise ratios (SNR) than srSE or twice-refocused spin-echo (trSE) schemes with intrinsic ECC. The proposed method employs dummy scans with DW gradients to drive eddy currents into a steady state before data acquisition. Parameters of the ECC postprocessing algorithm were also optimized. Simulations were performed to obtain minimum TE values for the proposed sequence and sequences with intrinsic ECC. Experimentally, the proposed method was compared with standard DW-trSE imaging, both in vitro and in vivo. Simulations showed substantially shorter TE for the proposed method than for methods with intrinsic ECC when using shortened echo readouts. Data of the proposed method showed a marked increase in SNR. A dummy scan duration of at least 1.5 s improved performance of the ECC postprocessing algorithm. Changes proposed for the DW-srSE sequence and for the parameter setting of the postprocessing ECC algorithm considerably reduced eddy-current artifacts and provided a higher SNR.

Effect of gradient pulse duration on MRI estimation of the diffusional kurtosis for a two-compartment exchange model

NASA Astrophysics Data System (ADS)

Jensen, Jens H.; Helpern, Joseph A.

2011-06-01

Hardware constraints typically require the use of extended gradient pulse durations for clinical applications of diffusion-weighted magnetic resonance imaging (DW-MRI), which can potentially influence the estimation of diffusion metrics. Prior studies have examined this effect for the apparent diffusion coefficient. This study employs a two-compartment exchange model in order to assess the gradient pulse duration sensitivity of the apparent diffusional kurtosis (ADK), a quantitative index of diffusional non-Gaussianity. An analytic expression is derived and numerically evaluated for parameter ranges relevant to DW-MRI of brain. It is found that the ADK differs from the true diffusional kurtosis by at most a few percent. This suggests that ADK estimates for brain may be robust with respect to changes in pulse gradient duration.

Distortion-free diffusion MRI using an MRI-guided Tri-Cobalt 60 radiotherapy system: Sequence verification and preliminary clinical experience.

PubMed

Gao, Yu; Han, Fei; Zhou, Ziwu; Cao, Minsong; Kaprealian, Tania; Kamrava, Mitchell; Wang, Chenyang; Neylon, John; Low, Daniel A; Yang, Yingli; Hu, Peng

2017-10-01

Monitoring tumor response during the course of treatment and adaptively modifying treatment plan based on tumor biological feedback may represent a new paradigm for radiotherapy. Diffusion MRI has shown great promises in assessing and predicting tumor response to radiotherapy. However, the conventional diffusion-weighted single-shot echo-planar-imaging (DW-ssEPI) technique suffers from limited resolution, severe distortion, and possibly inaccurate ADC at low field strength. The purpose of this work was to develop a reliable, accurate and distortion-free diffusion MRI technique that is practicable for longitudinal tumor response evaluation and adaptive radiotherapy on a 0.35 T MRI-guided radiotherapy system. A diffusion-prepared turbo spin echo readout (DP-TSE) sequence was developed and compared with the conventional diffusion-weighted single-shot echo-planar-imaging sequence on a 0.35 T MRI-guided radiotherapy system (ViewRay). A spatial integrity phantom was used to quantitate and compare the geometric accuracy of the two diffusion sequences for three orthogonal orientations. The apparent diffusion coefficient (ADC) accuracy was evaluated on a diffusion phantom under both 0 °C and room temperature to cover a diffusivity range between 0.40 × 10 -3 and 2.10 × 10 -3 mm 2 /s. Ten room temperature measurements repeated on five different days were conducted to assess the ADC reproducibility of DP-TSE. Two glioblastoma (GBM) and six sarcoma patients were included to examine the in vivo feasibility. The target registration error (TRE) was calculated to quantitate the geometric accuracy where structural CT or MR images were co-registered to the diffusion images as references. ADC maps from DP-TSE and DW-ssEPI were calculated and compared. A tube phantom was placed next to patients not treated on ViewRay, and ADCs of this reference tube were also compared. The proposed DP-TSE passed the spatial integrity test (< 1 mm within 100 mm radius and < 2 mm within 175 mm radius) under the three orthogonal orientations. The detected errors were 0.474 ± 0.355 mm, 0.475 ± 0.287 mm, and 0.546 ± 0.336 mm in the axial, coronal, and sagittal plane. DW-ssEPI, however, failed the tests due to severe distortion and low signal intensity. Noise correction must be performed for the DW-ssEPI to avoid ADC quantitation errors, whereas it is optional for DP-TSE. At 0 °C, the two sequences provided accurate quantitation with < 3% variation with the reference. In the room temperature study, discrepancies between ADCs from DP-TSE and the reference were within 4%, but could be as high as 8% for DW-ssEPI after the noise correction. Excellent ADC reproducibility with a coefficient of variation < 5% was observed among the 10 measurements of DP-TSE, indicating desirable robustness for ADC-based tumor response assessment. In vivo TRE in DP-TSE was less than 1.6 mm overall, whereas it could be greater than 12 mm in DW-ssEPI. For GBM patients, the CSF and brain tissue ADCs from DP-TSE were within the ranges found in literature. ADC differences between the two techniques were within 8% among the six sarcoma patients. For the reference tube that had a relatively low diffusivity, the two diffusion sequences provided matched measurements. A diffusion technique with excellent geometric fidelity, accurate, and reproducible ADC measurement was demonstrated for longitudinal tumor response assessment using a low-field MRI-guided radiotherapy system. © 2017 American Association of Physicists in Medicine.

Connective tissue of cervical carcinoma xenografts: associations with tumor hypoxia and interstitial fluid pressure and its assessment by DCE-MRI and DW-MRI.

PubMed

Hompland, Tord; Ellingsen, Christine; Galappathi, Kanthi; Rofstad, Einar K

2014-01-01

Abstract Background. A high fraction of stroma in malignant tissues is associated with tumor progression, metastasis, and poor prognosis. Possible correlations between the stromal and physiologic microenvironments of tumors and the potential of dynamic contrast-enhanced (DCE) and diffusion-weighted (DW) magnetic resonance imaging (MRI) in quantification of the stromal microenvironment were investigated in this study. Material and methods. CK-160 cervical carcinoma xenografts were used as preclinical tumor model. A total of 43 tumors were included in the study, and of these tumors, 17 were used to search for correlations between the stromal and physiologic microenvironments, 11 were subjected to DCE-MRI, and 15 were subjected to DW-MRI. DCE-MRI and DW-MRI were carried out at 1.5 T with a clinical MR scanner and a slotted tube resonator transceiver coil constructed for mice. Fraction of connective tissue (CTFCol) and fraction of hypoxic tissue (HFPim) were determined by immunohistochemistry. A Millar SPC 320 catheter was used to measure tumor interstitial fluid pressure (IFP). Results. CTFCol showed a positive correlation to IFP and an inverse correlation to HFPim. The apparent diffusion coefficient assessed by DW-MRI was inversely correlated to CTFCol, whereas no correlation was found between DCE-MRI-derived parameters and CTFCol. Conclusion. DW-MRI is a potentially useful method for characterizing the stromal microenvironment of tumors.

A reliability assessment of constrained spherical deconvolution-based diffusion-weighted magnetic resonance imaging in individuals with chronic stroke.

PubMed

Snow, Nicholas J; Peters, Sue; Borich, Michael R; Shirzad, Navid; Auriat, Angela M; Hayward, Kathryn S; Boyd, Lara A

2016-01-15

Diffusion-weighted magnetic resonance imaging (DW-MRI) is commonly used to assess white matter properties after stroke. Novel work is utilizing constrained spherical deconvolution (CSD) to estimate complex intra-voxel fiber architecture unaccounted for with tensor-based fiber tractography. However, the reliability of CSD-based tractography has not been established in people with chronic stroke. Establishing the reliability of CSD-based DW-MRI in chronic stroke. High-resolution DW-MRI was performed in ten adults with chronic stroke during two separate sessions. Deterministic region of interest-based fiber tractography using CSD was performed by two raters. Mean fractional anisotropy (FA), apparent diffusion coefficient (ADC), tract number, and tract volume were extracted from reconstructed fiber pathways in the corticospinal tract (CST) and superior longitudinal fasciculus (SLF). Callosal fiber pathways connecting the primary motor cortices were also evaluated. Inter-rater and test-retest reliability were determined by intra-class correlation coefficients (ICCs). ICCs revealed excellent reliability for FA and ADC in ipsilesional (0.86-1.00; p<0.05) and contralesional hemispheres (0.94-1.00; p<0.0001), for CST and SLF fibers; and excellent reliability for all metrics in callosal fibers (0.85-1.00; p<0.05). ICC ranged from poor to excellent for tract number and tract volume in ipsilesional (-0.11 to 0.92; p≤0.57) and contralesional hemispheres (-0.27 to 0.93; p≤0.64), for CST and SLF fibers. Like other select DW-MRI approaches, CSD-based tractography is a reliable approach to evaluate FA and ADC in major white matter pathways, in chronic stroke. Future work should address the reproducibility and utility of CSD-based metrics of tract number and tract volume. Copyright © 2015 Elsevier B.V. All rights reserved.

Influence of image registration on ADC images computed from free-breathing diffusion MRIs of the abdomen

NASA Astrophysics Data System (ADS)

Guyader, Jean-Marie; Bernardin, Livia; Douglas, Naomi H. M.; Poot, Dirk H. J.; Niessen, Wiro J.; Klein, Stefan

2014-03-01

The apparent diffusion coefficient (ADC) is an imaging biomarker providing quantitative information on the diffusion of water in biological tissues. This measurement could be of relevance in oncology drug development, but it suffers from a lack of reliability. ADC images are computed by applying a voxelwise exponential fitting to multiple diffusion-weighted MR images (DW-MRIs) acquired with different diffusion gradients. In the abdomen, respiratory motion induces misalignments in the datasets, creating visible artefacts and inducing errors in the ADC maps. We propose a multistep post-acquisition motion compensation pipeline based on 3D non-rigid registrations. It corrects for motion within each image and brings all DW-MRIs to a common image space. The method is evaluated on 10 datasets of free-breathing abdominal DW-MRIs acquired from healthy volunteers. Regions of interest (ROIs) are segmented in the right part of the abdomen and measurements are compared in the three following cases: no image processing, Gaussian blurring of the raw DW-MRIs and registration. Results show that both blurring and registration improve the visual quality of ADC images, but compared to blurring, registration yields visually sharper images. Measurement uncertainty is reduced both by registration and blurring. For homogeneous ROIs, blurring and registration result in similar median ADCs, which are lower than without processing. In a ROI at the interface between liver and kidney, registration and blurring yield different median ADCs, suggesting that uncorrected motion introduces a bias. Our work indicates that averaging procedures on the scanner should be avoided, as they remove the opportunity to perform motion correction.

Apparent diffusion coefficient of the normal human brain for various experimental conditions

NASA Astrophysics Data System (ADS)

Moraru, Luminita; Dimitrievici, Lucian

2017-01-01

Diffusion-Weighted Magnetic Resonance Imaging (DW-MRI) is being increasingly used to assess both brain tissues and cerebrospinal fluid integrity. In this paper we study inter-site reproducibility of the apparent diffusion coefficient values for the main cerebral tissues such as gray matter, white matter and into cerebrospinal fluid and for three different stacks of slices that were spaced at L = 79.8, 84.9 and 90 mm. We assessed the impact of the attenuation factor and diffusion gradient on the results reproducibility.

Demonstration of the reproducibility of free-breathing diffusion-weighted MRI and dynamic contrast enhanced MRI in children with solid tumours: a pilot study.

PubMed

Miyazaki, Keiko; Jerome, Neil P; Collins, David J; Orton, Matthew R; d'Arcy, James A; Wallace, Toni; Moreno, Lucas; Pearson, Andrew D J; Marshall, Lynley V; Carceller, Fernando; Leach, Martin O; Zacharoulis, Stergios; Koh, Dow-Mu

2015-09-01

The objectives are to examine the reproducibility of functional MR imaging in children with solid tumours using quantitative parameters derived from diffusion-weighted (DW-) and dynamic contrast enhanced (DCE-) MRI. Patients under 16-years-of age with confirmed diagnosis of solid tumours (n = 17) underwent free-breathing DW-MRI and DCE-MRI on a 1.5 T system, repeated 24 hours later. DW-MRI (6 b-values, 0-1000 sec/mm(2)) enabled monoexponential apparent diffusion coefficient estimation using all (ADC0-1000) and only ≥100 sec/mm(2) (ADC100-1000) b-values. DCE-MRI was used to derive the transfer constant (K(trans)), the efflux constant (kep), the extracellular extravascular volume (ve), and the plasma fraction (vp), using a study cohort arterial input function (AIF) and the extended Tofts model. Initial area under the gadolinium enhancement curve and pre-contrast T1 were also calculated. Percentage coefficients of variation (CV) of all parameters were calculated. The most reproducible cohort parameters were ADC100-1000 (CV = 3.26%), pre-contrast T1 (CV = 6.21%), and K(trans) (CV = 15.23%). The ADC100-1000 was more reproducible than ADC0-1000, especially extracranially (CV = 2.40% vs. 2.78%). The AIF (n = 9) derived from this paediatric population exhibited sharper and earlier first-pass and recirculation peaks compared with the literature's adult population average. Free-breathing functional imaging protocols including DW-MRI and DCE-MRI are well-tolerated in children aged 6 - 15 with good to moderate measurement reproducibility. • Diffusion MRI protocol is feasible and well-tolerated in a paediatric oncology population. • DCE-MRI for pharmacokinetic evaluation is feasible and well tolerated in a paediatric oncology population. • Paediatric arterial input function (AIF) shows systematic differences from the adult population-average AIF. • Variation of quantitative parameters from paired functional MRI measurements were within 20%.

Adjustable shunt valve-induced magnetic resonance imaging artifact: a comparative study.

PubMed

Toma, Ahmed K; Tarnaris, Andrew; Grieve, Joan P; Watkins, Laurence D; Kitchen, Neil D

2010-07-01

In this paper, the authors' goal was to compare the artifact induced by implanted (in vivo) adjustable shunt valves in spin echo, diffusion weighted (DW), and gradient echo MR imaging pulse sequences. The MR images obtained in 8 patients with proGAV and 6 patients with Strata II adjustable shunt valves were assessed for artifact areas in different planes as well as the total volume for different pulse sequences. Artifacts induced by the Strata II valve were significantly larger than those induced by proGAV valve in spin echo MR imaging pulse sequence (29,761 vs 2450 mm(3) on T2-weighted fast spin echo, p = 0.003) and DW images (100,138 vs 38,955 mm(3), p = 0.025). Artifacts were more marked on DW MR images than on spin echo pulse sequence for both valve types. Adjustable valve-induced artifacts can conceal brain pathology on MR images. This should influence the choice of valve implantation site and the type of valve used. The effect of artifacts on DW images should be highlighted pending the development of less MR imaging artifact-inducing adjustable shunt valves.

TU-AB-BRA-07: Distortion-Free 3D Diffusion MRI On An MRI-Guided Radiotherapy System for Longitudinal Tumor Response Assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, Y; Yang, Y; Rangwala, N

Purpose: To develop a reliable, 3D distortion-free diffusion MRI technique for longitudinal tumor response assessment and MRI-guided adaptive radiotherapy(RT). Methods: A diffusion prepared 3D turbo spin echo readout (DP-TSE) sequence was developed and compared with the conventional diffusion-weighted single-shot echo-planar-imaging (DW-ssEPI) sequence in a commercially available diffusion phantom, and one head-and-neck and one brain cancer patient on an MRI-guided RT system (ViewRay). In phantom study, the geometric fidelity was quantified as the ratio between the left-right (RL) and anterior-posterior (AP) dimension. Ten slices were measured on DP-TSE, DW-ssEPI and standard TSE images where the later was used as the geometricmore » reference. ADC accuracy was verified at both 0°C (reference ADC available) and room temperature with a range of diffusivity between 0.35 and 2.0*10{sup −3}mm{sup 2}/s. The ADC reproducibility was assessed based on 8 room-temperature measurements on 6 different days. In the pilot single-slice in-vivo study, CT images were used as the geometric reference, and ADC maps from both diffusion sequences were compared. Results: Distortion and susceptive-related artifact were severe in DW-ssEPI, with significantly lower RL/AP ratio (0.9579±0.0163) than DP-TSE (0.9990±0.0031) and TSE (0.9995±0.0031). ADCs from the two diffusion sequences both matched well with the vendor-provided values at 0°C; however DW-ssEPI fails to provide accurate ADC for high diffusivity vials at room temperature due to high noise level (10 times higher than DP-TSE). The DP-TSE sequence had excellent ADC reproducibility with <4% ADC variation among 8 separate measurements. In patient study, DP-TSE exhibited substantially improved geometric reliability. ROI analysis in ADC maps generated from DP-TSE and DW-ssEPI showed <5% difference where high b-value images were excluded from the latter approach due to excessive noise level. Conclusion: A diffusion MRI sequence with excellent geometric fidelity, accurate and highly reproducible ADC measurements was proposed for longitudinal tumor response assessment using an MRI-guided RT system. Yu Gao acknowledges research support from ViewRay.« less

Role of apparent diffusion coefficients with diffusion-weighted magnetic resonance imaging in differentiating between benign and malignant bone tumors.

PubMed

Wang, Tingting; Wu, Xiangru; Cui, Yanfen; Chu, Caiting; Ren, Gang; Li, Wenhua

2014-11-29

Benign and malignant bone tumors can present similar imaging features. This study aims to evaluate the significance of apparent diffusion coefficients (ADC) in differentiating between benign and malignant bone tumors. A total of 187 patients with 198 bone masses underwent diffusion-weighted (DW) magnetic resonance (MR) imaging. The ADC values in the solid components of the bone masses were assessed. Statistical differences between the mean ADC values in the different tumor types were determined by Student's t-test. Histological analysis showed that 84/198 (42.4%) of the bone masses were benign and 114/198 (57.6%) were malignant. There was a significant difference between the mean ADC values in the benign and malignant bone lesions (P<0.05). However, no significant difference was found in the mean ADC value between non-ossifying fibromas, osteofibrous dysplasia, and malignant bone tumors. When an ADC cutoff value≥1.10×10(-3) mm2/s was applied, malignant bone lesions were excluded with a sensitivity of 89.7%, a specificity of 84.5%, a positive predictive value of 82.6%, and a negative predictive value of 95.3%. The combination of DW imaging with ADC quantification and T2-weighted signal characteristics of the solid components in lesions can facilitate differentiation between benign and malignant bone tumors.

Fusion of Computed Tomography and PROPELLER Diffusion-Weighted Magnetic Resonance Imaging for the Detection and Localization of Middle Ear Cholesteatoma.

PubMed

Locketz, Garrett D; Li, Peter M M C; Fischbein, Nancy J; Holdsworth, Samantha J; Blevins, Nikolas H

2016-10-01

A method to optimize imaging of cholesteatoma by combining the strengths of available modalities will improve diagnostic accuracy and help to target treatment. To assess whether fusing Periodically Rotated Overlapping Parallel Lines With Enhanced Reconstruction (PROPELLER) diffusion-weighted magnetic resonance imaging (DW-MRI) with corresponding temporal bone computed tomography (CT) images could increase cholesteatoma diagnostic and localization accuracy across 6 distinct anatomical regions of the temporal bone. Case series and preliminary technology evaluation of adults with preoperative temporal bone CT and PROPELLER DW-MRI scans who underwent surgery for clinically suggested cholesteatoma at a tertiary academic hospital. When cholesteatoma was encountered surgically, the precise location was recorded in a diagram of the middle ear and mastoid. For each patient, the 3 image data sets (CT, PROPELLER DW-MRI, and CT-MRI fusion) were reviewed in random order for the presence or absence of cholesteatoma by an investigator blinded to operative findings. If cholesteatoma was deemed present on review of each imaging modality, the location of the lesion was mapped presumptively. Image analysis was then compared with surgical findings. Twelve adults (5 women and 7 men; median [range] age, 45.5 [19-77] years) were included. The use of CT-MRI fusion had greater diagnostic sensitivity (0.88 vs 0.75), positive predictive value (0.88 vs 0.86), and negative predictive value (0.75 vs 0.60) than PROPELLER DW-MRI alone. Image fusion also showed increased overall localization accuracy when stratified across 6 distinct anatomical regions of the temporal bone (localization sensitivity and specificity, 0.76 and 0.98 for CT-MRI fusion vs 0.58 and 0.98 for PROPELLER DW-MRI). For PROPELLER DW-MRI, there were 15 true-positive, 45 true-negative, 1 false-positive, and 11 false-negative results; overall accuracy was 0.83. For CT-MRI fusion, there were 20 true-positive, 45 true-negative, 1 false-positive, and 6 false-negative results; overall accuracy was 0.90. The poor anatomical spatial resolution of DW-MRI makes precise localization of cholesteatoma within the middle ear and mastoid a diagnostic challenge. This study suggests that the bony anatomic detail obtained via CT coupled with the excellent sensitivity and specificity of PROPELLER DW-MRI for cholesteatoma can improve both preoperative identification and localization of disease over DW-MRI alone.

Influence of image registration on apparent diffusion coefficient images computed from free-breathing diffusion MR images of the abdomen.

PubMed

Guyader, Jean-Marie; Bernardin, Livia; Douglas, Naomi H M; Poot, Dirk H J; Niessen, Wiro J; Klein, Stefan

2015-08-01

To evaluate the influence of image registration on apparent diffusion coefficient (ADC) images obtained from abdominal free-breathing diffusion-weighted MR images (DW-MRIs). A comprehensive pipeline based on automatic three-dimensional nonrigid image registrations is developed to compensate for misalignments in DW-MRI datasets obtained from five healthy subjects scanned twice. Motion is corrected both within each image and between images in a time series. ADC distributions are compared with and without registration in two abdominal volumes of interest (VOIs). The effects of interpolations and Gaussian blurring as alternative strategies to reduce motion artifacts are also investigated. Among the four considered scenarios (no processing, interpolation, blurring and registration), registration yields the best alignment scores. Median ADCs vary according to the chosen scenario: for the considered datasets, ADCs obtained without processing are 30% higher than with registration. Registration improves voxelwise reproducibility at least by a factor of 2 and decreases uncertainty (Fréchet-Cramér-Rao lower bound). Registration provides similar improvements in reproducibility and uncertainty as acquiring four times more data. Patient motion during image acquisition leads to misaligned DW-MRIs and inaccurate ADCs, which can be addressed using automatic registration. © 2014 Wiley Periodicals, Inc.

Monitoring the development of xenograft triple-negative breast cancer models using diffusion-weighted magnetic resonance imaging.

PubMed

Stephen, Renu M; Pagel, Mark D; Brown, Kathy; Baker, Amanda F; Meuillet, Emmanuelle J; Gillies, Robert J

2012-11-01

Evaluations of tumor growth rates and molecular biomarkers are traditionally used to assess new mouse models of human breast cancers. This study investigated the utility of diffusion weighted (DW)-magnetic resonance imaging (MRI) for evaluating cellular proliferation of new tumor models of triple-negative breast cancer, which may augment traditional analysis methods. Eleven human breast cancer cell lines were used to develop xenograft tumors in severe combined immunodeficient mice, with two of these cell lines exhibiting sufficient growth to be serially passaged. DW-MRI was performed to measure the distributions of the apparent diffusion coefficient (ADC) in these two tumor xenograft models, which showed a correlation with tumor growth rates and doubling times during each passage. The distributions of the ADC values were also correlated with expression of Ki67, a biomarker of cell proliferation, and hypoxia inducible factor (HIF)-1α and vascular endothelial growth factor receptor-2 (VEGFR2), which are essential proteins involved in regulating aerobic glycolysis and angiogenesis that support tumor cell proliferation. Although phosphatase and tensin homolog (PTEN) levels were different between the two xenograft models, AKT levels did not differ nor did they correlate with tumor growth. This last result demonstrates the complexity of signaling protein pathways and the difficulty in interpreting the effects of protein expression on tumor cell proliferation. In contrast, DW-MRI may be a more direct assessment of tumor growth and cancer cell proliferation.

Incorporation of diffusion-weighted magnetic resonance imaging data into a simple mathematical model of tumor growth

NASA Astrophysics Data System (ADS)

Atuegwu, N. C.; Colvin, D. C.; Loveless, M. E.; Xu, L.; Gore, J. C.; Yankeelov, T. E.

2012-01-01

We build on previous work to show how serial diffusion-weighted MRI (DW-MRI) data can be used to estimate proliferation rates in a rat model of brain cancer. Thirteen rats were inoculated intracranially with 9L tumor cells; eight rats were treated with the chemotherapeutic drug 1,3-bis(2-chloroethyl)-1-nitrosourea and five rats were untreated controls. All animals underwent DW-MRI immediately before, one day and three days after treatment. Values of the apparent diffusion coefficient (ADC) were calculated from the DW-MRI data and then used to estimate the number of cells in each voxel and also for whole tumor regions of interest. The data from the first two imaging time points were then used to estimate the proliferation rate of each tumor. The proliferation rates were used to predict the number of tumor cells at day three, and this was correlated with the corresponding experimental data. The voxel-by-voxel analysis yielded Pearson's correlation coefficients ranging from -0.06 to 0.65, whereas the region of interest analysis provided Pearson's and concordance correlation coefficients of 0.88 and 0.80, respectively. Additionally, the ratio of positive to negative proliferation values was used to separate the treated and control animals (p <0.05) at an earlier point than the mean ADC values. These results further illustrate how quantitative measurements of tumor state obtained non-invasively by imaging can be incorporated into mathematical models that predict tumor growth.

Cerebral edema induced in mice by a convulsive dose of soman. Evaluation through diffusion-weighted magnetic resonance imaging and histology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Testylier, Guy; Lahrech, Hana; Universite Joseph Fourier, Grenoble, F-38043

2007-04-15

Purpose: In the present study, diffusion-weighted magnetic resonance imaging (DW-MRI) and histology were used to assess cerebral edema and lesions in mice intoxicated by a convulsive dose of soman, an organophosphate compound acting as an irreversible cholinesterase inhibitor. Methods: Three hours and 24 h after the intoxication with soman (172 {mu}g/kg), the mice were anesthetized with an isoflurane/N{sub 2}O mixture and their brain examined with DW-MRI. After the imaging sessions, the mice were sacrificed for histological analysis of their brain. Results: A decrease in the apparent diffusion coefficient (ADC) was detected as soon as 3 h after the intoxication andmore » was found strongly enhanced at 24 h. A correlation was obtained between the ADC change and the severity of the overall brain damage (edema and cellular degeneration): the more severe the damage, the stronger the ADC drop. Anesthesia was shown to interrupt soman-induced seizures and to attenuate edema and cell change in certain sensitive brain areas. Finally, brain water content was assessed using the traditional dry/wet weight method. A significant increase of brain water was observed following the intoxication. Conclusions: The ADC decrease observed in the present study suggests that brain edema in soman poisoning is mainly intracellular and cytotoxic. Since entry of water into Brain was also evidenced, this type of edema is certainly mixed with others (vasogenic, hydrostatic, osmotic). The present study confirms the potential of DW-MRI as a non-invasive tool for monitoring the acute neuropathological consequences (edema and neurodegeneration) of soman-induced seizures.« less

Prediction of subacute infarct size in acute middle cerebral artery stroke: comparison of perfusion-weighted imaging and apparent diffusion coefficient maps.

PubMed

Drier, Aurélie; Tourdias, Thomas; Attal, Yohan; Sibon, Igor; Mutlu, Gurkan; Lehéricy, Stéphane; Samson, Yves; Chiras, Jacques; Dormont, Didier; Orgogozo, Jean-Marc; Dousset, Vincent; Rosso, Charlotte

2012-11-01

To compare perfusion-weighted (PW) imaging and apparent diffusion coefficient (ADC) maps in prediction of infarct size and growth in patients with acute middle cerebral artery infarct. This study was approved by the local institutional review board. Written informed consent was obtained from all 80 patients. Subsequent infarct volume and growth on follow-up magnetic resonance (MR) images obtained within 6 days were compared with the predictions based on PW images by using a time-to-peak threshold greater than 4 seconds and ADC maps obtained less than 12 hours after middle cerebral artery infarct. ADC- and PW imaging-predicted infarct growth areas and infarct volumes were correlated with subsequent infarct growth and follow-up diffusion-weighted (DW) imaging volumes. The impact of MR imaging time delay on the correlation coefficient between the predicted and subsequent infarct volumes and individual predictions of infarct growth by using receiver operating characteristic curves were assessed. The infarct volume measurements were highly reproducible (concordance correlation coefficient [CCC] of 0.965 and 95% confidence interval [CI]: 0.949, 0.976 for acute DW imaging; CCC of 0.995 and 95% CI: 0.993, 0.997 for subacute DW imaging). The subsequent infarct volume correlated (P<.0001) with ADC- (ρ=0.853) and PW imaging- (ρ=0.669) predicted volumes. The correlation was higher for ADC-predicted volume than for PW imaging-predicted volume (P<.005), but not when the analysis was restricted to patients without recanalization (P=.07). The infarct growth correlated (P<.0001) with PW imaging-DW imaging mismatch (ρ=0.470) and ADC-DW imaging mismatch (ρ=0.438), without significant differences between both methods (P=.71). The correlations were similar among time delays with ADC-predicted volumes but decreased with PW imaging-based volumes beyond the therapeutic window. Accuracies of ADC- and PW imaging-based predictions of infarct growth in an individual prediction were similar (area under the receiver operating characteristic curve [AUC] of 0.698 and 95% CI: 0.585, 0.796 vs AUC of 0.749 and 95% CI: 0.640, 0.839; P=.48). The ADC-based method was as accurate as the PW imaging-based method for evaluating infarct growth and size in the subacute phase. © RSNA, 2012

Evaluating the diagnostic sensitivity of computed diffusion-weighted MR imaging in the detection of breast cancer.

PubMed

O'Flynn, Elizabeth A M; Blackledge, Matthew; Collins, David; Downey, Katherine; Doran, Simon; Patel, Hardik; Dumonteil, Sam; Mok, Wing; Leach, Martin O; Koh, Dow-Mu

2016-07-01

To evaluate the diagnostic sensitivity of computed diffusion-weighted (DW)-MR imaging for the detection of breast cancer. Local research ethics approval was obtained. A total of 61 women (median 48 years) underwent dynamic contrast enhanced (DCE)- and DW-MR between January 2011 and March 2012, including 27 with breast cancer on core biopsy and 34 normal cases. Standard ADC maps using all four b values (0, 350, 700, 1150) were used to generate computed DW-MR images at b = 1500 s/mm(2) and b = 2000 s/mm(2) . Four image sets were read sequentially by two readers: acquired b = 1150 s/mm(2) , computed b = 1500 s/mm(2) and b = 2000 s/mm(2) , and DCE-MR at an early time point. Cancer detection was rated using a five-point scale; image quality and background suppression were rated using a four-point scale. The diagnostic sensitivity for breast cancer detection was compared using the McNemar test and inter-reader agreement with a Kappa value. Computed DW-MR resulted in higher overall diagnostic sensitivity with b = 2000 s/mm(2) having a mean diagnostic sensitivity of 76% (range 49.8-93.7%) and b = 1500 s/mm(2) having a mean diagnostic sensitivity of 70.3% (range 32-97.7%) compared with 44.4% (range 25.5-64.7%) for acquired b = 1150 s/mm(2) (both p = 0.0001). Computed DW-MR images produced better image quality and background suppression (mean scores for both readers: 2.55 and 2.9 for b 1500 s/mm(2) ; 2.55 and 3.15 for b 2000 s/mm(2) , respectively) than the acquired b value 1150 s/mm(2) images (mean scores for both readers: 2.4 and 2.45, respectively). Computed DW-MR imaging has the potential to improve the diagnostic sensitivity of breast cancer detection compared to acquired DW-MR. J. Magn. Reson. Imaging 2016;44:130-137. © 2016 Wiley Periodicals, Inc.

Diagnostic value of apparent diffusion coefficients to differentiate benign from malignant vertebral bone marrow lesions.

PubMed

Balliu, E; Vilanova, J C; Peláez, I; Puig, J; Remollo, S; Barceló, C; Barceló, J; Pedraza, S

2009-03-01

The aim of this study is to evaluate the value of the apparent diffusion coefficient (ADC) obtained in diffusion-weighted (DW) MR sequences for the differentiation between malignant and benign bone marrow lesions. Forty-five patients with altered signal intensity vertebral bodies on conventional MR sequences were included. The cause of altered signal intensity was benign osteoporotic collapse in 16, acute neoplastic infiltration in 15, and infectious processes in 14; based on plain-film, CT, bone scintigraphy, conventional MR studies, biopsy or follow-up. All patients underwent isotropic DW MR images (multi-shot EPI, b values of 0 and 500 s/mm(2)). Signal intensity at DW MR images was evaluated and ADC values were calculated and compared between malignancy, benign edema and infectious spondylitis. Acute malignant fractures were hyperintense compared to normal vertebral bodies on the diffusion-weighted sequence, except in one patient with sclerotic metastases. Mean ADC value from benign edema (1.9+/-0.39 x 10(-3) mm(2)/s) was significantly (p<0.0001) higher than untreated metastasic lesions (0.9+/-1.3 x 10(-3)mm (2)/s). Mean ADC value of infectious spondilytis (0.96+/-0.49 x 10(-3) mm(2)/s) was not statistically (p>0.05) different from untreated metastasic lesions. ADC value was low (0.75 x 10(-3) mm(2)/s) in one case of subacute benign fracture. ADC values are a useful complementary tool to characterize bone marrow lesions, in order to distinguish acute benign fractures from malignant or infectious bone lesions. However, ADC values are not valuable in order to differentiate malignancy from infection.

Diffusion-weighted magnetic resonance imaging with apparent diffusion coefficient (ADC) determination in normal and pathological fetal kidneys.

PubMed

Chaumoitre, K; Colavolpe, N; Shojai, R; Sarran, A; D' Ercole, C; Panuel, M

2007-01-01

To assess the use of diffusion-weighted magnetic resonance imaging (DW-MRI) in the evaluation of the fetal kidney and to estimate age-dependent changes in the apparent diffusion coefficient (ADC) of normal and pathological fetal kidneys. DW-MRI was performed on a 1.5-T machine at 23-38 gestational weeks in 51 pregnant women in whom the fetal kidneys were normal and in 10 whose fetuses had renal pathology (three with suspected nephropathy, three with renal tract dilatation, one with unilateral renal venous thrombosis, and three with twin-twin transfusion syndrome (TTTS)). The ADC was measured in an approximately 1-cm2 region of interest within the renal parenchyma. ADC values in normal renal parenchyma ranged from 1.1 to 1.8 10(-3) mm2 s-1. There was no significant age-dependent change in the ADC of normal kidneys. In cases of nephropathy, the ADC value was not always pathological but an ADC map could show abnormal findings. In cases of dilatation, the ADC value was difficult to determine when the dilatation was huge. In cases of TTTS, the ADC of the donor twin was higher than that of the recipient twin and the difference seemed to be related to the severity of the syndrome. Evaluation of the ADC for fetal kidneys is feasible. Fetal measurement of the ADC value and ADC maps may be useful tools with which to explore the fetal kidney when used in conjunction with current methods. DW-MR images, ADC value and ADC map seem to be useful in cases of suspected nephropathy (hyperechoic kidneys), dilated kidney and vascular pathology (renal venous thrombosis, TTTS). Copyright (c) 2006 ISUOG.

Metastatic Renal Cell Carcinoma Masquerading as Jugular Foramen Paraganglioma: A Role for Novel Magnetic Resonance Imaging.

PubMed

Thomas, Andrew J; Wiggins, Richard H; Gurgel, Richard K

2017-08-01

To describe a case of metastatic renal cell carcinoma (RCC) masquerading as a jugular foramen paraganglioma (JP). To compare imaging findings between skull base metastatic RCC and histologically proven paraganglioma. A case of unexpected metastatic skull base RCC is reviewed. Computed tomography (CT) and magnetic resonance imaging (MRI) were compared between 3 confirmed cases of JP and our case of metastatic RCC. Diffusion-weighted MRI (DW-MRI) sequences and computed apparent diffusion coefficient (ADC) values were compared between these entities. A 55-year-old man presents with what appears clinically and radiographically to be JP. The tumor was resected, then discovered on postoperative pathology to be metastatic RCC. Imaging was retrospectively compared between 3 histologically confirmed cases of JP and our case of skull base RCC. The RCC metastasis was indistinguishable from JP on CT and traditional MRI but distinct by ADC values calculated from DW-MRI. Metastatic RCC at the skull base may mimic the clinical presentation and radiographic appearance of JP. The MRI finding of flow voids is seen in both paraganglioma and metastatic RCC. Diffusion-weighted MRI is able to distinguish these entities, highlighting its potential utility in distinguishing skull base lesions.

Optimized magnetic resonance diffusion protocol for ex-vivo whole human brain imaging with a clinical scanner

NASA Astrophysics Data System (ADS)

Scherrer, Benoit; Afacan, Onur; Stamm, Aymeric; Singh, Jolene; Warfield, Simon K.

2015-03-01

Diffusion-weighted magnetic resonance imaging (DW-MRI) provides a novel insight into the brain to facilitate our understanding of the brain connectivity and microstructure. While in-vivo DW-MRI enables imaging of living patients and longitudinal studies of brain changes, post-mortem ex-vivo DW-MRI has numerous advantages. Ex-vivo imaging benefits from greater resolution and sensitivity due to the lack of imaging time constraints; the use of tighter fitting coils; and the lack of movement artifacts. This allows characterization of normal and abnormal tissues with unprecedented resolution and sensitivity, facilitating our ability to investigate anatomical structures that are inaccessible in-vivo. This also offers the opportunity to develop today novel imaging biomarkers that will, with tomorrow's MR technology, enable improved in-vivo assessment of the risk of disease in an individual. Post-mortem studies, however, generally rely on the fixation of specimen to inhibit tissue decay which starts as soon as tissue is deprived from its blood supply. Unfortunately, fixation of tissues substantially alters tissue diffusivity profiles. In addition, ex-vivo DW-MRI requires particular care when packaging the specimen because the presence of microscopic air bubbles gives rise to geometric and intensity image distortion. In this work, we considered the specific requirements of post-mortem imaging and designed an optimized protocol for ex-vivo whole brain DW-MRI using a human clinical 3T scanner. Human clinical 3T scanners are available to a large number of researchers and, unlike most animal scanners, have a bore diameter large enough to image a whole human brain. Our optimized protocol will facilitate widespread ex-vivo investigations of large specimen.

Normal Central Zone of the Prostate and Central Zone Involvement by Prostate Cancer: Clinical and MR Imaging Implications

PubMed Central

Akin, Oguz; Franiel, Tobias; Goldman, Debra A.; Udo, Kazuma; Touijer, Karim A.; Reuter, Victor E.; Hricak, Hedvig

2012-01-01

Purpose: To describe the anatomic features of the central zone of the prostate on T2-weighted and diffusion-weighted (DW) magnetic resonance (MR) images and evaluate the diagnostic performance of MR imaging in detection of central zone involvement by prostate cancer. Materials and Methods: The institutional review board waived informed consent and approved this retrospective, HIPAA-compliant study of 211 patients who underwent T2-weighted and DW MR imaging of the prostate before radical prostatectomy. Whole-mount step-section pathologic findings were the reference standard. Two radiologists independently recorded the visibility, MR signal intensity, size, and symmetry of the central zone and scored the likelihood of central zone involvement by cancer on T2-weighted MR images and on T2-weighted MR images plus apparent diffusion coefficient (ADC) maps generated from the DW MR images. Descriptive summary statistics were calculated for central zone imaging features. Sensitivity, specificity, and area under the curve were used to evaluate reader performance in detecting central zone involvement. Results: For readers 1 and 2, the central zone was visible, at least partially, in 177 (84%) and 170 (81%) of 211 patients, respectively. The most common imaging appearance of the central zone was symmetric, homogeneous low signal intensity. Cancers involving the central zone had higher prostate-specific antigen values, Gleason scores, and rates of extracapsular extension and seminal vesicle invasion compared with cancers not involving the central zone (P < .05). Area under the curve, sensitivity, and specificity in detecting central zone involvement were 0.70, 0.30, and 0.96 for reader 1 and 0.65, 0.35, and 0.93 for reader 2, and these values did not differ significantly between T2-weighted imaging and T2-weighted imaging plus ADC maps. Conclusion: The central zone was visualized in most patients. Cancers involving the central zone were associated with more aggressive disease than those without central zone involvement. © RSNA, 2012 PMID:22357889

Experimental dehydration of natural obsidian and estimation of DH2O at low water contents

NASA Technical Reports Server (NTRS)

Jambon, A.; Zhang, Y.; Stolper, E. M.

1992-01-01

Water diffusion experiments were carried out by dehydrating rhyolitic obsidian from Valles Caldera (New Mexico, USA) at 510-980 degrees C. The starting glass wafers contained approximately 0.114 wt% total water, lower than any glasses previously investigated for water diffusion. Weight loss due to dehydration was measured as a function of experiment duration, which permits determination of mean bulk water diffusivity, mean Dw. These diffusivities are in the range of 2.6 to 18 X 10(-14) m2/s and can be fit with the following Arrhenius equation: ln mean Dw (m2/s) = -(25.10 +/- 1.29) - (46,480 +/- 11,400) (J/mol) / RT, except for two replicate runs at 510 degrees C which give mean Dw values much lower than that defined by the above equation. When interpreted according to a model of water speciation in which molecular H2O is the diffusing species with concentration-independent diffusivity while OH units do not contribute to the transport but react to provide H2O, the data (except for the 510 degrees C data) are in agreement with extrapolation from previous results and hence extend the previous data base and provide a test of the applicability of the model to very low water contents. Mean bulk water diffusivities are about two orders of magnitude less than molecular H2O diffusivities because the fraction of molecular H2O out of total water is very small at 0.114 wt% total water and less. The 510 degrees C experimental results can be interpreted as due to slow kinetics of OH to H2O interconversion at low temperatures.

Experimental dehydration of natural obsidian and estimation of DH2O at low water contents.

PubMed

Jambon, A; Zhang, Y; Stolper, E M

1992-01-01

Water diffusion experiments were carried out by dehydrating rhyolitic obsidian from Valles Caldera (New Mexico, USA) at 510-980 degrees C. The starting glass wafers contained approximately 0.114 wt% total water, lower than any glasses previously investigated for water diffusion. Weight loss due to dehydration was measured as a function of experiment duration, which permits determination of mean bulk water diffusivity, mean Dw. These diffusivities are in the range of 2.6 to 18 X 10(-14) m2/s and can be fit with the following Arrhenius equation: ln mean Dw (m2/s) = -(25.10 +/- 1.29) - (46,480 +/- 11,400) (J/mol) / RT, except for two replicate runs at 510 degrees C which give mean Dw values much lower than that defined by the above equation. When interpreted according to a model of water speciation in which molecular H2O is the diffusing species with concentration-independent diffusivity while OH units do not contribute to the transport but react to provide H2O, the data (except for the 510 degrees C data) are in agreement with extrapolation from previous results and hence extend the previous data base and provide a test of the applicability of the model to very low water contents. Mean bulk water diffusivities are about two orders of magnitude less than molecular H2O diffusivities because the fraction of molecular H2O out of total water is very small at 0.114 wt% total water and less. The 510 degrees C experimental results can be interpreted as due to slow kinetics of OH to H2O interconversion at low temperatures.

Comparison of Free-Breathing With Navigator-Triggered Technique in Diffusion Weighted Imaging for Evaluation of Small Hepatocellular Carcinoma: Effect on Image Quality and Intravoxel Incoherent Motion Parameters.

PubMed

Shan, Yan; Zeng, Meng-su; Liu, Kai; Miao, Xi-Yin; Lin, Jiang; Fu, Cai xia; Xu, Peng-ju

2015-01-01

To evaluate the effect on image quality and intravoxel incoherent motion (IVIM) parameters of small hepatocellular carcinoma (HCC) from choice of either free-breathing (FB) or navigator-triggered (NT) diffusion-weighted (DW) imaging. Thirty patients with 37 small HCCs underwent IVIM DW imaging using 12 b values (0-800 s/mm) with 2 sequences: NT, FB. A biexponential analysis with the Bayesian method yielded true diffusion coefficient (D), pseudodiffusion coefficient (D*), and perfusion fraction (f) in small HCCs and liver parenchyma. Apparent diffusion coefficient (ADC) was also calculated. The acquisition time and image quality scores were assessed for 2 sequences. Independent sample t test was used to compare image quality, signal intensity ratio, IVIM parameters, and ADC values between the 2 sequences; reproducibility of IVIM parameters, and ADC values between 2 sequences was assessed with the Bland-Altman method (BA-LA). Image quality with NT sequence was superior to that with FB acquisition (P = 0.02). The mean acquisition time for FB scheme was shorter than that of NT sequence (6 minutes 14 seconds vs 10 minutes 21 seconds ± 10 seconds P < 0.01). The signal intensity ratio of small HCCs did not vary significantly between the 2 sequences. The ADC and IVIM parameters from the 2 sequences show no significant difference. Reproducibility of D*and f parameters in small HCC was poor (BA-LA: 95% confidence interval, -180.8% to 189.2% for D* and -133.8% to 174.9% for f). A moderate reproducibility of D and ADC parameters was observed (BA-LA: 95% confidence interval, -83.5% to 76.8% for D and -74.4% to 88.2% for ADC) between the 2 sequences. The NT DW imaging technique offers no advantage in IVIM parameters measurements of small HCC except better image quality, whereas FB technique offers greater confidence in fitted diffusion parameters for matched acquisition periods.

Diffusion-weighted imaging of the liver with multiple b values: effect of diffusion gradient polarity and breathing acquisition on image quality and intravoxel incoherent motion parameters--a pilot study.

PubMed

Dyvorne, Hadrien A; Galea, Nicola; Nevers, Thomas; Fiel, M Isabel; Carpenter, David; Wong, Edmund; Orton, Matthew; de Oliveira, Andre; Feiweier, Thorsten; Vachon, Marie-Louise; Babb, James S; Taouli, Bachir

2013-03-01

To optimize intravoxel incoherent motion (IVIM) diffusion-weighted (DW) imaging by estimating the effects of diffusion gradient polarity and breathing acquisition scheme on image quality, signal-to-noise ratio (SNR), IVIM parameters, and parameter reproducibility, as well as to investigate the potential of IVIM in the detection of hepatic fibrosis. In this institutional review board-approved prospective study, 20 subjects (seven healthy volunteers, 13 patients with hepatitis C virus infection; 14 men, six women; mean age, 46 years) underwent IVIM DW imaging with four sequences: (a) respiratory-triggered (RT) bipolar (BP) sequence, (b) RT monopolar (MP) sequence, (c) free-breathing (FB) BP sequence, and (d) FB MP sequence. Image quality scores were assessed for all sequences. A biexponential analysis with the Bayesian method yielded true diffusion coefficient (D), pseudodiffusion coefficient (D*), and perfusion fraction (PF) in liver parenchyma. Mixed-model analysis of variance was used to compare image quality, SNR, IVIM parameters, and interexamination variability between the four sequences, as well as the ability to differentiate areas of liver fibrosis from normal liver tissue. Image quality with RT sequences was superior to that with FB acquisitions (P = .02) and was not affected by gradient polarity. SNR did not vary significantly between sequences. IVIM parameter reproducibility was moderate to excellent for PF and D, while it was less reproducible for D*. PF and D were both significantly lower in patients with hepatitis C virus than in healthy volunteers with the RT BP sequence (PF = 13.5% ± 5.3 [standard deviation] vs 9.2% ± 2.5, P = .038; D = [1.16 ± 0.07] × 10(-3) mm(2)/sec vs [1.03 ± 0.1] × 10(-3) mm(2)/sec, P = .006). The RT BP DW imaging sequence had the best results in terms of image quality, reproducibility, and ability to discriminate between healthy and fibrotic liver with biexponential fitting.

Readout-Segmented Echo-Planar Imaging in Diffusion-Weighted MR Imaging in Breast Cancer: Comparison with Single-Shot Echo-Planar Imaging in Image Quality

PubMed Central

Kim, Yun Ju; Kang, Bong Joo; Park, Chang Suk; Kim, Hyeon Sook; Son, Yo Han; Porter, David Andrew; Song, Byung Joo

2014-01-01

Objective The purpose of this study was to compare the image quality of standard single-shot echo-planar imaging (ss-EPI) and that of readout-segmented EPI (rs-EPI) in patients with breast cancer. Materials and Methods Seventy-one patients with 74 breast cancers underwent both ss-EPI and rs-EPI. For qualitative comparison of image quality, three readers independently assessed the two sets of diffusion-weighted (DW) images. To evaluate geometric distortion, a comparison was made between lesion lengths derived from contrast enhanced MR (CE-MR) images and those obtained from the corresponding DW images. For assessment of image parameters, signal-to-noise ratio (SNR), lesion contrast, and contrast-to-noise ratio (CNR) were calculated. Results The rs-EPI was superior to ss-EPI in most criteria regarding the qualitative image quality. Anatomical structure distinction, delineation of the lesion, ghosting artifact, and overall image quality were significantly better in rs-EPI. Regarding the geometric distortion, lesion length on ss-EPI was significantly different from that of CE-MR, whereas there were no significant differences between CE-MR and rs-EPI. The rs-EPI was superior to ss-EPI in SNR and CNR. Conclusion Readout-segmented EPI is superior to ss-EPI in the aspect of image quality in DW MR imaging of the breast. PMID:25053898

DW MRI at 3.0 T versus FDG PET/CT for detection of malignant pulmonary tumors.

PubMed

Zhang, Jian; Cui, Long-Biao; Tang, Xing; Ren, Xin-Ling; Shi, Jie-Ran; Yang, Hai-Nan; Zhang, Yan; Li, Zhi-Kui; Wu, Chang-Gui; Jian, Wen; Zhao, Feng; Ti, Xin-Yu; Yin, Hong

2014-02-01

Emerging evidence suggests that diffusion-weighted magnetic resonance imaging (DW MRI) could be useful for tumor detection with N and M staging of lung cancer in place of fluorine 18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT). DW MRI at 3.0 T and FDG PET/CT were performed before therapy in 113 patients with pulmonary nodules. Mean apparent diffusion coefficient (ADC), maximal standardized uptake value (SUVmax ) and Ki-67 scores were assessed. Quantitatively, specificity and accuracy of ADC (91.7 and 92.9%, respectively) were significantly higher than those of SUVmax (66.7 and 77.9% respectively, p < 0.05), although sensitivity was not significantly different between them (93.5 and 83.1%, p > 0.05). Qualitatively, sensitivity, specificity and accuracy of DW MRI (96.1, 83.3 and 92.0%, respectively) were also not significantly different from that of FDG PET/CT (88.3, 83.3 and 86.7%, respectively, p > 0.05). Significant negative correlation was found between Ki-67 score and ADC (r = -0.66, p < 0.05), ADC and SUVmax (r = -0.37, p < 0.05), but not between Ki-67 score and SUVmax (r = -0.11, p > 0.05). In conclusion, quantitative and qualitative assessments for detection of malignant pulmonary tumors with DW MRI at 3.0 T are superior to those with FDG PET/CT. Furthermore, ADC could predict the malignancy of lung cancer. © 2013 UICC.

Diffusion-weighted imaging of the prostate: should we use quantitative metrics to better characterize focal lesions originating in the peripheral zone?

PubMed

Pierre, Thibaut; Cornud, Francois; Colléter, Loïc; Beuvon, Frédéric; Foissac, Frantz; Delongchamps, Nicolas B; Legmann, Paul

2018-05-01

To compare inter-reader concordance and accuracy of qualitative diffusion-weighted (DW) PIRADSv2.0 score with those of quantitative DW-MRI for the diagnosis of peripheral zone prostate cancer. Two radiologists independently assigned a DW-MRI-PIRADS score to 92 PZ-foci, in 74 patients (64.3±5.6 years old; median PSA level: 8 ng/ml, normal DRE in 70 men). A standardised ADCmean and nine ADC-derived parameters were measured, including ADCratios with the whole-prostate (WP-ADCratio) or the mirror-PZ (mirror-ADCratio) as reference areas. Surgical histology and MRI-TRUS fusion-biopsy were the reference for tumours and benign foci, respectively. Inter-reader agreement was assessed by the Cohen-kappa-coefficient and the intraclass correlation coefficient (ICC). Univariate-multivariate regressions determined the most predictive factor for cancer. Fifty lesions were malignant. Inter-reader concordance was fair for qualitative assessment, but excellent for quantitative assessment for all quantitative variables. At univariate analysis, ADCmean, WP-ADCratio and WL-ADCmean performed equally, but significantly better than the mirror-ADCratio (p<0.001). At multivariate analysis, the only independent variable significantly associated with malignancy was the whole-prostate-ADCratio. At a cut-off value of 0.68, sensitivity was 94-90 % and specificity was 60-38 % for readers 1 and 2, respectively. The whole-prostate-ADCratio improved the qualitative inter-reader concordance and characterisation of focal PZ-lesions. • Inter-reader concordance of DW PI-RADSv2.0 score for PZ lesions was only fair. • Using a standardised ADCmean measurement and derived DW-quantitative parameters, concordance was excellent. • The whole-prostate ADCratio performed significantly better than the mirror-ADCratio for cancer detection. • At a cut-off of 0.68, sensitivity values of WP-ADCratio were 94-90 %. • The whole-prostate ADCratio may circumvent variations of ADC metrics across centres.

Rotating single-shot acquisition (RoSA) with composite reconstruction for fast high-resolution diffusion imaging.

PubMed

Wen, Qiuting; Kodiweera, Chandana; Dale, Brian M; Shivraman, Giri; Wu, Yu-Chien

2018-01-01

To accelerate high-resolution diffusion imaging, rotating single-shot acquisition (RoSA) with composite reconstruction is proposed. Acceleration was achieved by acquiring only one rotating single-shot blade per diffusion direction, and high-resolution diffusion-weighted (DW) images were reconstructed by using similarities of neighboring DW images. A parallel imaging technique was implemented in RoSA to further improve the image quality and acquisition speed. RoSA performance was evaluated by simulation and human experiments. A brain tensor phantom was developed to determine an optimal blade size and rotation angle by considering similarity in DW images, off-resonance effects, and k-space coverage. With the optimal parameters, RoSA MR pulse sequence and reconstruction algorithm were developed to acquire human brain data. For comparison, multishot echo planar imaging (EPI) and conventional single-shot EPI sequences were performed with matched scan time, resolution, field of view, and diffusion directions. The simulation indicated an optimal blade size of 48 × 256 and a 30 ° rotation angle. For 1 × 1 mm 2 in-plane resolution, RoSA was 12 times faster than the multishot acquisition with comparable image quality. With the same acquisition time as SS-EPI, RoSA provided superior image quality and minimum geometric distortion. RoSA offers fast, high-quality, high-resolution diffusion images. The composite image reconstruction is model-free and compatible with various diffusion computation approaches including parametric and nonparametric analyses. Magn Reson Med 79:264-275, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

Diffusion-weighted magnetic resonance imaging reveals the effects of different cooling temperatures on the diffusion of water molecules and perfusion within human skeletal muscle.

PubMed

Yanagisawa, O; Fukubayashi, T

2010-11-01

To evaluate the effect of local cooling on the diffusion of water molecules and perfusion within muscle at different cooling temperatures. Magnetic resonance diffusion-weighted (DW) images of the leg (seven males) were obtained before and after 30 min cooling (0, 10, and 20°C), and after a 30 min recovery period. Two types of apparent diffusion coefficient (ADC; ADC1, reflecting both water diffusion and perfusion within muscle, and ADC2, approximating the true water diffusion coefficient) of the ankle dorsiflexors were calculated from DW images. T2-weighted images were also obtained to calculate T2 values of the ankle dorsiflexors. The skin temperature was measured before, during, and after cooling. Both ADC values significantly decreased after cooling under all cooling conditions; the rate of decrease depended on the cooling temperature used (ADC1: -36% at 0°C, -27.8% at 10°C, and -22.6% at 20°C; ADC2: -26% at 0°C, -21.1% at 10°C, and -14.6% at 20°C). These significant decreases were maintained during the recovery period. Conversely, the T2 value showed no significant changes. Under all cooling conditions, skin temperature significantly decreased during cooling; the rate of decrease depended on the cooling temperature used (-74.8% at 0°C, -51.1% at 10°C, and -26.8% at 20°C). Decreased skin temperatures were not restored to pre-cooling values during the recovery period under any cooling conditions. Local cooling decreased the water diffusion and perfusion within muscle with decreased skin temperature; the rates of decrease depended on the cooling temperature used. These decreases were maintained for 30 min after cooling. Copyright © 2010 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

A comparative quantitative analysis of magnetic susceptibility artifacts in echo planar and PROPELLER diffusion-weighted images

NASA Astrophysics Data System (ADS)

Cho, Jae-Hwan; Lee, Hae-Kag; Yang, Han-Joon; Lee, Gui-Won; Park, Yong-Soon; Chung, Woon-Kwan

2013-01-01

In this study, the authors investigated whether periodically-rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) diffusion-weighted imaging (DWI) can remove magnetic susceptibility artifacts and compared apparent diffusion coefficient (ADC) values for PROPELLER DWI and the common echo planar (EP) DWI. Twenty patients that underwent brain MRI with a metal dental implant were selected. A 3.0T MR scanner was then used to obtain EP DWI, PROPELLER DWI, and corresponding apparent diffusion coefficient (ADC) maps for a b-value of 0 and 1,000 s/mm2. The frequencies of magnetic susceptibility artifacts in four parts of the brain (bilateral temporal lobes, pons, and orbit) were selected. In the ADC maps, we measured the ADC values of both sides of the temporal lobe and the pons. According to the study results, the frequency of magnetic susceptibility artifacts in PROPELLER DW images was lower than it was in EP DW images. In ADC maps, the ADC values of the bilateral temporal lobes and the pons were all higher in PROPELLER ADC maps than in EP ADC maps. Our findings show that when a high-field MRI machine is used, magnetic susceptibility artifacts can distort anatomical structures and produce high-intensity signals. Furthermore, our findings suggest that in many cases, PROPELLER DWI would be helpful in terms of achieving a correct diagnosis.

Whole-body diffusion-weighted magnetic resonance imaging (WB-DW-MRI) vs choline-positron emission tomography-computed tomography (choline-PET/CT) for selecting treatments in recurrent prostate cancer.

PubMed

Conde-Moreno, A J; Herrando-Parreño, G; Muelas-Soria, R; Ferrer-Rebolleda, J; Broseta-Torres, R; Cozar-Santiago, M P; García-Piñón, F; Ferrer-Albiach, C

2017-05-01

To determine the effectiveness of whole-body diffusion-weighted magnetic resonance imaging (WB-DW-MRI) in detecting metastases by comparing the results with those from choline-positron emission tomography-computed tomography (choline-PET/CT) in patients with biochemical relapse after primary treatment, and no metastases in bone scintigraphy, CT and/or pelvic MRI, or metastatic/oligometastatic prostate cancer (PCa). Patients with this disease profile who could benefit from treatment with stereotactic body radiation therapy (SBRT) were selected and their responses to these techniques were rated. This was a prospective, controlled, unicentric study, involving 46 consecutive patients from our centre who presented biochemical relapse after adjuvant, salvage or radical treatment with external beam radiotherapy, or brachytherapy. After initial tests (bone scintigraphy, CT, pelvic MRI), 35 patients with oligometastases or without them were selected. 11 patients with multiple metastases were excluded from the study. WB-DW-MRI and choline-PET/CT was then performed on each patient within 1 week. The results were interpreted by specialists in nuclear medicine and MRI. If they were candidates for treatment with ablative SBRT (SABR), they were then evaluated every three months with both tests. Choline-PET/CT detected lesions in 16 patients that were not observable using WB-DW-MRI. The results were consistent in seven patients and in three cases, a lesion was observed using WB-DW-MRI that was not detected with choline-PET/CT. The Kappa value obtained was 0.133 (p = 0.089); the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of WB-DW-MRI were estimated at 44.93, 64.29, 86.11, and 19.15%, respectively. For choline-PET/CT patients, the sensitivity, specificity, PPV, and NPV were 97.10, 58.33, 93.06, and 77.78%, respectively. Choline-PET/CT has a high global sensitivity while WB-DW-MRI has a high specificity, and so they are complementary techniques. Future studies with more enrolled patients and a longer follow-up period will be required to confirm these data. The initial data show that the best technique for evaluating response after SBRT is choline-PET/CT. Trial registration number NCT02858128.

Repeated diffusion MRI reveals earliest time point for stratification of radiotherapy response in brain metastases

NASA Astrophysics Data System (ADS)

Mahmood, Faisal; Johannesen, Helle H.; Geertsen, Poul; Hansen, Rasmus H.

2017-04-01

An imaging biomarker for early prediction of treatment response potentially provides a non-invasive tool for better prognostics and individualized management of the disease. Radiotherapy (RT) response is generally related to changes in gross tumor volume manifesting months later. In this prospective study we investigated the apparent diffusion coefficient (ADC), perfusion fraction and pseudo diffusion coefficient derived from diffusion weighted MRI as potential early biomarkers for radiotherapy response of brain metastases. It was a particular aim to assess the optimal time point for acquiring the DW-MRI scan during the course of treatment, since to our knowledge this important question has not been addressed directly in previous studies. Twenty-nine metastases (N  =  29) from twenty-one patients, treated with whole-brain fractionated external beam RT were analyzed. Patients were scanned with a 1 T MRI system to acquire DW-, T2*W-, T2W- and T1W scans, before start of RT, at each fraction and at follow up two to three months after RT. The DW-MRI parameters were derived using regions of interest based on high b-value images (b  =  800 s mm-2). Both volumetric and RECIST criteria were applied for response evaluation. It was found that in non-responding metastases the mean ADC decreased and in responding metastases it increased. The volume based response proved to be far more consistently predictable by the ADC change found at fraction number 7 and later, compared to the linear response (RECIST). The perfusion fraction and pseudo diffusion coefficient did not show sufficient prognostic value with either response assessment criteria. In conclusion this study shows that the ADC derived using high b-values may be a reliable biomarker for early assessment of radiotherapy response for brain metastases patients. The earliest response stratification can be achieved using two DW-MRI scans, one pre-treatment and one at treatment day 7-9 (equivalent to 21 Gy).

A quantitative comparison of two methods to correct eddy current-induced distortions in DT-MRI.

PubMed

Muñoz Maniega, Susana; Bastin, Mark E; Armitage, Paul A

2007-04-01

Eddy current-induced geometric distortions of single-shot, diffusion-weighted, echo-planar (DW-EP) images are a major confounding factor to the accurate determination of water diffusion parameters in diffusion tensor MRI (DT-MRI). Previously, it has been suggested that these geometric distortions can be removed from brain DW-EP images using affine transformations determined from phantom calibration experiments using iterative cross-correlation (ICC). Since this approach was first described, a number of image-based registration methods have become available that can also correct eddy current-induced distortions in DW-EP images. However, as yet no study has investigated whether separate eddy current calibration or image-based registration provides the most accurate way of removing these artefacts from DT-MRI data. Here we compare how ICC phantom calibration and affine FLIRT (http://www.fmrib.ox.ac.uk), a popular image-based multi-modal registration method that can correct both eddy current-induced distortions and bulk subject motion, perform when registering DW-EP images acquired with different slice thicknesses (2.8 and 5 mm) and b-values (1000 and 3000 s/mm(2)). With the use of consistency testing, it was found that ICC was a more robust algorithm for correcting eddy current-induced distortions than affine FLIRT, especially at high b-value and small slice thickness. In addition, principal component analysis demonstrated that the combination of ICC phantom calibration (to remove eddy current-induced distortions) with rigid body FLIRT (to remove bulk subject motion) provided a more accurate registration of DT-MRI data than that achieved by affine FLIRT.

Quantitative evaluation of benign and malignant vertebral fractures with diffusion-weighted MRI: what is the optimum combination of b values for ADC-based lesion differentiation with the single-shot turbo spin-echo sequence?

PubMed

Geith, Tobias; Schmidt, Gerwin; Biffar, Andreas; Dietrich, Olaf; Duerr, Hans Roland; Reiser, Maximilian; Baur-Melnyk, Andrea

2014-09-01

The purpose of our study was to determine the optimum combination of b values for calculating the apparent diffusion coefficient (ADC) using a diffusion-weighted (DW) single-shot turbo spin-echo (TSE) sequence in the differentiation between acute benign and malignant vertebral body fractures. Twenty-six patients with osteoporotic (mean age, 69 years; range, 31.5-86.2 years) and 20 patients with malignant vertebral fractures (mean age, 63.4 years; range, 24.7-86.4 years) were studied. T1-weighted, STIR, and T2-weighted sequences were acquired at 1.5 T. A DW single-shot TSE sequence at different b values (100, 250, 400, and 600 s/mm(2)) was applied. On the DW images for each evaluated fracture, an ROI was manually adapted to the area of hyperintense signal intensity on STIR-hypointense signal on T1-weighted images. For each ROI, nine different combinations of two, three, and four b values were used to calculate the ADC using a least-squares algorithm. The Student t test and Mann-Whitney U test were used to determine significant differences between benign and malignant fractures. An ROC analysis and the Youden index were used to determine cutoff values for assessment of the highest sensitivity and specificity for the different ADC values. The positive (PPV) and negative predictive values (NPV) were also determined. All calculated ADCs (except the combination of b = 400 s/mm(2) and b = 600 s/mm(2)) showed statistically significant differences between benign and malignant vertebral body fractures, with benign fractures having higher ADCs than malignant ones. The use of higher b values resulted in lower ADCs than those calculated with low b values. The highest AUC (0.85) showed the ADCs calculated with b = 100 and 400 s/mm(2), and the second highest AUC (0.829) showed the ADCs calculated with b = 100, 250, and 400 s/mm(2). The Youden index with equal weight given to sensitivity and specificity suggests use of an ADC calculated with b = 100, 250, and 400 s/mm(2) (cutoff ADC, < 1.7 × 10(-3) mm(2)/s) to best diagnose malignancy (sensitivity, 85%; specificity, 84.6%; PPV, 81.0%; NPV, 88.0%). ADCs calculated with a combination of low to intermediate b values (b = 100, 250, and 400 s/mm(2)) provide the best diagnostic performance of a DW single-shot TSE sequence to differentiate acute benign and malignant vertebral body fractures.

Validation of the Dominant Sequence Paradigm and Role of Dynamic Contrast-enhanced Imaging in PI-RADS Version 2.

PubMed

Greer, Matthew D; Shih, Joanna H; Lay, Nathan; Barrett, Tristan; Kayat Bittencourt, Leonardo; Borofsky, Samuel; Kabakus, Ismail M; Law, Yan Mee; Marko, Jamie; Shebel, Haytham; Mertan, Francesca V; Merino, Maria J; Wood, Bradford J; Pinto, Peter A; Summers, Ronald M; Choyke, Peter L; Turkbey, Baris

2017-12-01

Purpose To validate the dominant pulse sequence paradigm and limited role of dynamic contrast material-enhanced magnetic resonance (MR) imaging in the Prostate Imaging Reporting and Data System (PI-RADS) version 2 for prostate multiparametric MR imaging by using data from a multireader study. Materials and Methods This HIPAA-compliant retrospective interpretation of prospectively acquired data was approved by the local ethics committee. Patients were treatment-naïve with endorectal coil 3-T multiparametric MR imaging. A total of 163 patients were evaluated, 110 with prostatectomy after multiparametric MR imaging and 53 with negative multiparametric MR imaging and systematic biopsy findings. Nine radiologists participated in this study and interpreted images in 58 patients, on average (range, 56-60 patients). Lesions were detected with PI-RADS version 2 and were compared with whole-mount prostatectomy findings. Probability of cancer detection for overall, T2-weighted, and diffusion-weighted (DW) imaging PI-RADS scores was calculated in the peripheral zone (PZ) and transition zone (TZ) by using generalized estimating equations. To determine dominant pulse sequence and benefit of dynamic contrast-enhanced (DCE) imaging, odds ratios (ORs) were calculated as the ratio of odds of cancer of two consecutive scores by logistic regression. Results A total of 654 lesions (420 in the PZ) were detected. The probability of cancer detection for PI-RADS category 2, 3, 4, and 5 lesions was 15.7%, 33.1%, 70.5%, and 90.7%, respectively. DW imaging outperformed T2-weighted imaging in the PZ (OR, 3.49 vs 2.45; P = .008). T2-weighted imaging performed better but did not clearly outperform DW imaging in the TZ (OR, 4.79 vs 3.77; P = .494). Lesions classified as PI-RADS category 3 at DW MR imaging and as positive at DCE imaging in the PZ showed a higher probability of cancer detection than did DCE-negative PI-RADS category 3 lesions (67.8% vs 40.0%, P = .02). The addition of DCE imaging to DW imaging in the PZ was beneficial (OR, 2.0; P = .027), with an increase in the probability of cancer detection of 15.7%, 16.0%, and 9.2% for PI-RADS category 2, 3, and 4 lesions, respectively. Conclusion DW imaging outperforms T2-weighted imaging in the PZ; T2-weighted imaging did not show a significant difference when compared with DW imaging in the TZ by PI-RADS version 2 criteria. The addition of DCE imaging to DW imaging scores in the PZ yields meaningful improvements in probability of cancer detection. © RSNA, 2017 An earlier incorrect version of this article appeared online. This article was corrected on July 27, 2017. Online supplemental material is available for this article.

Fiber estimation and tractography in diffusion MRI: Development of simulated brain images and comparison of multi-fiber analysis methods at clinical b-values

PubMed Central

Wilkins, Bryce; Lee, Namgyun; Gajawelli, Niharika; Law, Meng; Leporé, Natasha

2015-01-01

Advances in diffusion-weighted magnetic resonance imaging (DW-MRI) have led to many alternative diffusion sampling strategies and analysis methodologies. A common objective among methods is estimation of white matter fiber orientations within each voxel, as doing so permits in-vivo fiber-tracking and the ability to study brain connectivity and networks. Knowledge of how DW-MRI sampling schemes affect fiber estimation accuracy, and consequently tractography and the ability to recover complex white-matter pathways, as well as differences between results due to choice of analysis method and which method(s) perform optimally for specific data sets, all remain important problems, especially as tractography-based studies become common. In this work we begin to address these concerns by developing sets of simulated diffusion-weighted brain images which we then use to quantitatively evaluate the performance of six DW-MRI analysis methods in terms of estimated fiber orientation accuracy, false-positive (spurious) and false-negative (missing) fiber rates, and fiber-tracking. The analysis methods studied are: 1) a two-compartment “ball and stick” model (BSM) (Behrens et al., 2003); 2) a non-negativity constrained spherical deconvolution (CSD) approach (Tournier et al., 2007); 3) analytical q-ball imaging (QBI) (Descoteaux et al., 2007); 4) q-ball imaging with Funk-Radon and Cosine Transform (FRACT) (Haldar and Leahy, 2013); 5) q-ball imaging within constant solid angle (CSA) (Aganj et al., 2010); and 6) a generalized Fourier transform approach known as generalized q-sampling imaging (GQI) (Yeh et al., 2010). We investigate these methods using 20, 30, 40, 60, 90 and 120 evenly distributed q-space samples of a single shell, and focus on a signal-to-noise ratio (SNR = 18) and diffusion-weighting (b = 1000 s/mm2) common to clinical studies. We found the BSM and CSD methods consistently yielded the least fiber orientation error and simultaneously greatest detection rate of fibers. Fiber detection rate was found to be the most distinguishing characteristic between the methods, and a significant factor for complete recovery of tractography through complex white-matter pathways. For example, while all methods recovered similar tractography of prominent white matter pathways of limited fiber crossing, CSD (which had the highest fiber detection rate, especially for voxels containing three fibers) recovered the greatest number of fibers and largest fraction of correct tractography for a complex three-fiber crossing region. The synthetic data sets, ground-truth, and tools for quantitative evaluation are publically available on the NITRC website as the project “Simulated DW-MRI Brain Data Sets for Quantitative Evaluation of Estimated Fiber Orientations” at http://www.nitrc.org/projects/sim_dwi_brain PMID:25555998

Fiber estimation and tractography in diffusion MRI: development of simulated brain images and comparison of multi-fiber analysis methods at clinical b-values.

PubMed

Wilkins, Bryce; Lee, Namgyun; Gajawelli, Niharika; Law, Meng; Leporé, Natasha

2015-04-01

Advances in diffusion-weighted magnetic resonance imaging (DW-MRI) have led to many alternative diffusion sampling strategies and analysis methodologies. A common objective among methods is estimation of white matter fiber orientations within each voxel, as doing so permits in-vivo fiber-tracking and the ability to study brain connectivity and networks. Knowledge of how DW-MRI sampling schemes affect fiber estimation accuracy, tractography and the ability to recover complex white-matter pathways, differences between results due to choice of analysis method, and which method(s) perform optimally for specific data sets, all remain important problems, especially as tractography-based studies become common. In this work, we begin to address these concerns by developing sets of simulated diffusion-weighted brain images which we then use to quantitatively evaluate the performance of six DW-MRI analysis methods in terms of estimated fiber orientation accuracy, false-positive (spurious) and false-negative (missing) fiber rates, and fiber-tracking. The analysis methods studied are: 1) a two-compartment "ball and stick" model (BSM) (Behrens et al., 2003); 2) a non-negativity constrained spherical deconvolution (CSD) approach (Tournier et al., 2007); 3) analytical q-ball imaging (QBI) (Descoteaux et al., 2007); 4) q-ball imaging with Funk-Radon and Cosine Transform (FRACT) (Haldar and Leahy, 2013); 5) q-ball imaging within constant solid angle (CSA) (Aganj et al., 2010); and 6) a generalized Fourier transform approach known as generalized q-sampling imaging (GQI) (Yeh et al., 2010). We investigate these methods using 20, 30, 40, 60, 90 and 120 evenly distributed q-space samples of a single shell, and focus on a signal-to-noise ratio (SNR = 18) and diffusion-weighting (b = 1000 s/mm(2)) common to clinical studies. We found that the BSM and CSD methods consistently yielded the least fiber orientation error and simultaneously greatest detection rate of fibers. Fiber detection rate was found to be the most distinguishing characteristic between the methods, and a significant factor for complete recovery of tractography through complex white-matter pathways. For example, while all methods recovered similar tractography of prominent white matter pathways of limited fiber crossing, CSD (which had the highest fiber detection rate, especially for voxels containing three fibers) recovered the greatest number of fibers and largest fraction of correct tractography for complex three-fiber crossing regions. The synthetic data sets, ground-truth, and tools for quantitative evaluation are publically available on the NITRC website as the project "Simulated DW-MRI Brain Data Sets for Quantitative Evaluation of Estimated Fiber Orientations" at http://www.nitrc.org/projects/sim_dwi_brain. Copyright © 2014 Elsevier Inc. All rights reserved.

Accelerating Fibre Orientation Estimation from Diffusion Weighted Magnetic Resonance Imaging Using GPUs

PubMed Central

Hernández, Moisés; Guerrero, Ginés D.; Cecilia, José M.; García, José M.; Inuggi, Alberto; Jbabdi, Saad; Behrens, Timothy E. J.; Sotiropoulos, Stamatios N.

2013-01-01

With the performance of central processing units (CPUs) having effectively reached a limit, parallel processing offers an alternative for applications with high computational demands. Modern graphics processing units (GPUs) are massively parallel processors that can execute simultaneously thousands of light-weight processes. In this study, we propose and implement a parallel GPU-based design of a popular method that is used for the analysis of brain magnetic resonance imaging (MRI). More specifically, we are concerned with a model-based approach for extracting tissue structural information from diffusion-weighted (DW) MRI data. DW-MRI offers, through tractography approaches, the only way to study brain structural connectivity, non-invasively and in-vivo. We parallelise the Bayesian inference framework for the ball & stick model, as it is implemented in the tractography toolbox of the popular FSL software package (University of Oxford). For our implementation, we utilise the Compute Unified Device Architecture (CUDA) programming model. We show that the parameter estimation, performed through Markov Chain Monte Carlo (MCMC), is accelerated by at least two orders of magnitude, when comparing a single GPU with the respective sequential single-core CPU version. We also illustrate similar speed-up factors (up to 120x) when comparing a multi-GPU with a multi-CPU implementation. PMID:23658616

Multiparametric Magnetic Resonance Imaging of the Prostate for Tumour Detection and Local Staging: Imaging in 1.5T and Histopathologic Correlation.

PubMed

Loggitsi, Dimitra; Gyftopoulos, Anastasios; Economopoulos, Nikolaos; Apostolaki, Aikaterini; Kalogeropoulos, Theodoros; Thanos, Anastasios; Alexopoulou, Efthimia; Kelekis, Nikolaos L

2017-11-01

The study sought to prospectively evaluate which technique among T2-weighted images, dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI), diffusion-weighted (DW) MRI, or a combination of the 2, is best suited for prostate cancer detection and local staging. Twenty-seven consecutive patients with biopsy-proven adenocarcinoma of the prostate underwent MRI on a 1.5T scanner with a surface phased-array coil prior radical prostatectomy. Combined anatomical and functional imaging was performed with the use of T2-weighted sequences, DCE MRI, and DW MRI. We compared the imaging results with whole mount histopathology. For the multiparametric approach, significantly higher sensitivity values, that is, 53% (95% confidence interval [CI]: 41.0-64.1) were obtained as compared with each modality alone or any combination of the 3 modalities (P < .05). The specificity for this multiparametric approach, being 90.3% (95% CI: 86.3-93.3) was not significantly higher (P < .05) as compared with the values of the combination of T2+DCE MRI, DW+DCE MRI, or DCE MRI alone. Among the 3 techniques, DCE had the best performance for tumour detection in both the peripheral and the transition zone. High negative predictive value rates (>86%) were obtained for both tumour detection and local staging. The combination of T2-weighted sequences, DCE MRI, and DW MRI yields higher diagnostic performance for tumour detection and local staging than can any of these techniques alone or even any combination of them. Copyright © 2017 Canadian Association of Radiologists. Published by Elsevier Inc. All rights reserved.

Evaluation of dual-source parallel RF excitation for diffusion-weighted whole-body MR imaging with background body signal suppression at 3.0 T.

PubMed

Mürtz, Petra; Kaschner, Marius; Träber, Frank; Kukuk, Guido M; Büdenbender, Sarah M; Skowasch, Dirk; Gieseke, Jürgen; Schild, Hans H; Willinek, Winfried A

2012-11-01

To evaluate the use of dual-source parallel RF excitation (TX) for diffusion-weighted whole-body MRI with background body signal suppression (DWIBS) at 3.0 T. Forty consecutive patients were examined on a clinical 3.0-T MRI system using a diffusion-weighted (DW) spin-echo echo-planar imaging sequence with a combination of short TI inversion recovery and slice-selective gradient reversal fat suppression. DWIBS of the neck (n=5), thorax (n=8), abdomen (n=6) and pelvis (n=21) was performed both with TX (2:56 min) and with standard single-source RF excitation (4:37 min). The quality of DW images and reconstructed inverted maximum intensity projections was visually judged by two readers (blinded to acquisition technique). Signal homogeneity and fat suppression were scored as "improved", "equal", "worse" or "ambiguous". Moreover, the apparent diffusion coefficient (ADC) values were measured in muscles, urinary bladder, lymph nodes and lesions. By the use of TX, signal homogeneity was "improved" in 25/40 and "equal" in 15/40 cases. Fat suppression was "improved" in 17/40 and "equal" in 23/40 cases. These improvements were statistically significant (p<0.001, Wilcoxon signed-rank test). In five patients, fluid-related dielectric shading was present, which improved remarkably. The ADC values did not significantly differ for the two RF excitation methods (p=0.630 over all data, pairwise Student's t-test). Dual-source parallel RF excitation improved image quality of DWIBS at 3.0 T with respect to signal homogeneity and fat suppression, reduced scan time by approximately one-third, and did not influence the measured ADC values. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Automated pixel-wise brain tissue segmentation of diffusion-weighted images via machine learning.

PubMed

Ciritsis, Alexander; Boss, Andreas; Rossi, Cristina

2018-04-26

The diffusion-weighted (DW) MR signal sampled over a wide range of b-values potentially allows for tissue differentiation in terms of cellularity, microstructure, perfusion, and T 2 relaxivity. This study aimed to implement a machine learning algorithm for automatic brain tissue segmentation from DW-MRI datasets, and to determine the optimal sub-set of features for accurate segmentation. DWI was performed at 3 T in eight healthy volunteers using 15 b-values and 20 diffusion-encoding directions. The pixel-wise signal attenuation, as well as the trace and fractional anisotropy (FA) of the diffusion tensor, were used as features to train a support vector machine classifier for gray matter, white matter, and cerebrospinal fluid classes. The datasets of two volunteers were used for validation. For each subject, tissue classification was also performed on 3D T 1 -weighted data sets with a probabilistic framework. Confusion matrices were generated for quantitative assessment of image classification accuracy in comparison with the reference method. DWI-based tissue segmentation resulted in an accuracy of 82.1% on the validation dataset and of 82.2% on the training dataset, excluding relevant model over-fitting. A mean Dice coefficient (DSC) of 0.79 ± 0.08 was found. About 50% of the classification performance was attributable to five features (i.e. signal measured at b-values of 5/10/500/1200 s/mm 2 and the FA). This reduced set of features led to almost identical performances for the validation (82.2%) and the training (81.4%) datasets (DSC = 0.79 ± 0.08). Machine learning techniques applied to DWI data allow for accurate brain tissue segmentation based on both morphological and functional information. Copyright © 2018 John Wiley & Sons, Ltd.

Diffusion-weighted Imaging of the Liver with Multiple b Values: Effect of Diffusion Gradient Polarity and Breathing Acquisition on Image Quality and Intravoxel Incoherent Motion Parameters—A Pilot Study

PubMed Central

Dyvorne, Hadrien A.; Galea, Nicola; Nevers, Thomas; Fiel, M. Isabel; Carpenter, David; Wong, Edmund; Orton, Matthew; de Oliveira, Andre; Feiweier, Thorsten; Vachon, Marie-Louise; Babb, James S.

2013-01-01

Purpose: To optimize intravoxel incoherent motion (IVIM) diffusion-weighted (DW) imaging by estimating the effects of diffusion gradient polarity and breathing acquisition scheme on image quality, signal-to-noise ratio (SNR), IVIM parameters, and parameter reproducibility, as well as to investigate the potential of IVIM in the detection of hepatic fibrosis. Materials and Methods: In this institutional review board–approved prospective study, 20 subjects (seven healthy volunteers, 13 patients with hepatitis C virus infection; 14 men, six women; mean age, 46 years) underwent IVIM DW imaging with four sequences: (a) respiratory-triggered (RT) bipolar (BP) sequence, (b) RT monopolar (MP) sequence, (c) free-breathing (FB) BP sequence, and (d) FB MP sequence. Image quality scores were assessed for all sequences. A biexponential analysis with the Bayesian method yielded true diffusion coefficient (D), pseudodiffusion coefficient (D*), and perfusion fraction (PF) in liver parenchyma. Mixed-model analysis of variance was used to compare image quality, SNR, IVIM parameters, and interexamination variability between the four sequences, as well as the ability to differentiate areas of liver fibrosis from normal liver tissue. Results: Image quality with RT sequences was superior to that with FB acquisitions (P = .02) and was not affected by gradient polarity. SNR did not vary significantly between sequences. IVIM parameter reproducibility was moderate to excellent for PF and D, while it was less reproducible for D*. PF and D were both significantly lower in patients with hepatitis C virus than in healthy volunteers with the RT BP sequence (PF = 13.5% ± 5.3 [standard deviation] vs 9.2% ± 2.5, P = .038; D = [1.16 ± 0.07] × 10−3 mm2/sec vs [1.03 ± 0.1] × 10−3 mm2/sec, P = .006). Conclusion: The RT BP DW imaging sequence had the best results in terms of image quality, reproducibility, and ability to discriminate between healthy and fibrotic liver with biexponential fitting. © RSNA, 2012 PMID:23220895

Phase correction for three-dimensional (3D) diffusion-weighted interleaved EPI using 3D multiplexed sensitivity encoding and reconstruction (3D-MUSER).

PubMed

Chang, Hing-Chiu; Hui, Edward S; Chiu, Pui-Wai; Liu, Xiaoxi; Chen, Nan-Kuei

2018-05-01

Three-dimensional (3D) multiplexed sensitivity encoding and reconstruction (3D-MUSER) algorithm is proposed to reduce aliasing artifacts and signal corruption caused by inter-shot 3D phase variations in 3D diffusion-weighted echo planar imaging (DW-EPI). 3D-MUSER extends the original framework of multiplexed sensitivity encoding (MUSE) to a hybrid k-space-based reconstruction, thereby enabling the correction of inter-shot 3D phase variations. A 3D single-shot EPI navigator echo was used to measure inter-shot 3D phase variations. The performance of 3D-MUSER was evaluated by analyses of point-spread function (PSF), signal-to-noise ratio (SNR), and artifact levels. The efficacy of phase correction using 3D-MUSER for different slab thicknesses and b-values were investigated. Simulations showed that 3D-MUSER could eliminate artifacts because of through-slab phase variation and reduce noise amplification because of SENSE reconstruction. All aliasing artifacts and signal corruption in 3D interleaved DW-EPI acquired with different slab thicknesses and b-values were reduced by our new algorithm. A near-whole brain single-slab 3D DTI with 1.3-mm isotropic voxel acquired at 1.5T was successfully demonstrated. 3D phase correction for 3D interleaved DW-EPI data is made possible by 3D-MUSER, thereby improving feasible slab thickness and maximum feasible b-value. Magn Reson Med 79:2702-2712, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

Fetal lung apparent diffusion coefficient measurement using diffusion-weighted MRI at 3 Tesla: Correlation with gestational age.

PubMed

Afacan, Onur; Gholipour, Ali; Mulkern, Robert V; Barnewolt, Carol E; Estroff, Judy A; Connolly, Susan A; Parad, Richard B; Bairdain, Sigrid; Warfield, Simon K

2016-12-01

To evaluate the feasibility of using diffusion-weighted magnetic resonance imaging (DW-MRI) to assess the fetal lung apparent diffusion coefficient (ADC) at 3 Tesla (T). Seventy-one pregnant women (32 second trimester, 39 third trimester) were scanned with a twice-refocused Echo-planar diffusion-weighted imaging sequence with 6 different b-values in 3 orthogonal diffusion orientations at 3T. After each scan, a region-of-interest (ROI) mask was drawn to select a region in the fetal lung and an automated robust maximum likelihood estimation algorithm was used to compute the ADC parameter. The amount of motion in each scan was visually rated. When scans with unacceptable levels of motion were eliminated, the lung ADC values showed a strong association with gestational age (P < 0.01), increasing dramatically between 16 and 27 weeks and then achieving a plateau around 27 weeks. We show that to get reliable estimates of ADC values of fetal lungs, a multiple b-value acquisition, where motion is either corrected or considered, can be performed. J. Magn. Reson. Imaging 2016;44:1650-1655. © 2016 International Society for Magnetic Resonance in Medicine.

Preoperative grading of supratentorial gliomas using high or standard b-value diffusion-weighted MR imaging at 3T.

PubMed

Cihangiroglu, M M; Ozturk-Isik, E; Firat, Z; Kilickesmez, O; Ulug, A M; Ture, U

2017-03-01

The goal of this study was to compare diffusion-weighted magnetic resonance imaging (DW-MRI) using high b-value (b=3000s/mm 2 ) to DW-MRI using standard b-value (b=1000s/mm 2 ) in the preoperative grading of supratentorial gliomas. Fifty-three patients with glioma had brain DW-MRI at 3T using two different b-values (b=1000s/mm 2 and b=3000s/mm 2 ). There were 35 men and 18 women with a mean age of 40.5±17.1 years (range: 18-79 years). Mean, minimum, maximum, and range of apparent diffusion coefficient (ADC) values for solid tumor ROIs (ADC mean , ADC min , ADC max , and ADC diff ), and the normalized ADC (ADC ratio ) were calculated. A Kruskal-Wallis statistic with Bonferroni correction for multiple comparisons was applied to detect significant ADC parameter differences between tumor grades by including or excluding 19 patients with an oligodendroglioma. Receiver operating characteristic curve analysis was conducted to define appropriate cutoff values for grading gliomas. No differences in ADC derived parameters were found between grade II and grade III gliomas. Mean ADC values using standard b-value were 1.17±0.27×10 -3 mm 2 /s [range: 0.63-1.61], 1.05±0.22×10 -3 mm 2 /s [range: 0.73-1.33], and 0.86±0.23×10 -3 mm 2 /s [range: 0.52-1.46] for grades II, III and IV gliomas, respectively. Using high b-value, mean ADC values were 0.89±0.24×10 -3 mm 2 /s [range: 0.42-1.25], 0.82±0.20×10 -3 mm 2 /s [range: 0.56-1.10], and 0.59±0.17×10 -3 mm 2 /s [range: 0.40-1.01] for grades II, III and IV gliomas, respectively. ADC mean , ADC ratio , ADC max , and ADC min were different between grade II and grade IV gliomas at both standard and high b-values. Differences in ADC mean , ADC max , and ADC diff were found between grade III and grade IV only using high b-value. ADC parameters derived from DW-MRI using a high b-value allows a better differential diagnosis of gliomas, especially for differentiating grades III and IV, than those derived from DW-MRI using a standard b-value. Copyright © 2016 Éditions françaises de radiologie. Published by Elsevier Masson SAS. All rights reserved.

High b Value (2,000 s/mm2) Diffusion-Weighted Magnetic Resonance Imaging in Prostate Cancer at 3 Tesla: Comparison with 1,000 s/mm2 for Tumor Conspicuity and Discrimination of Aggressiveness

PubMed Central

Tamada, Tsutomu; Kanomata, Naoki; Sone, Teruki; Jo, Yoshimasa; Miyaji, Yoshiyuki; Higashi, Hiroki; Yamamoto, Akira; Ito, Katsuyoshi

2014-01-01

Objective The objective of our study was to investigate tumor conspicuity and the discrimination potential for tumor aggressiveness on diffusion-weighted magnetic resonance imaging (DW-MRI) with high b value at 3-T. Materials and Methods The institutional review board approved this study and waived the requirement for informed consent. A total of 50 patients with prostate cancer (69 cancer foci; 48 in the PZ, 20 in the TZ, and one in whole prostate) who underwent multiparametric prostate MRI including DW-MRI (b values: 0, 1000 s/mm2 and 0, 2000 s/mm2) on a 3-T system were included. Lesion conspicuity score (LCS) using visual assessment (1 = invisible for surrounding normal site; 2 = slightly high intensity; 3 = moderately high; and 4 = very high) and tumor-normal signal intensity ratio (TNR) were assessed, and apparent diffusion coefficient (ADC, ×10−3 mm2/s) of the tumor regions and normal regions were measured. Results Mean LCS and TNR at 0, 2000 s/mm2 was significantly higher than those at 0, 1000 s/mm2 (p<0.001 for both). In addition, ADC at both 0, 1000 and 0, 2000 s/mm2 was found to distinguish intermediate or high risk cancer with Gleason score ≥7 from low risk cancer with Gleason score ≤6 (p<0.001 for both). Furthermore, ADC of tumor regions correlated with Gleason score at both 0, 1000 s/mm2 (ρ = −0.602; p<0.001) and 0, 2000 s/mm2 (ρ = −0.645; p<0.001). Conclusions For tumor conspicuity and characterization of prostate cancer on DW-MRI of 3-T MRI, b = 0, 2000 s/mm2 is more useful than b = 0, 1000 s/mm2. PMID:24802652

High b value (2,000 s/mm2) diffusion-weighted magnetic resonance imaging in prostate cancer at 3 Tesla: comparison with 1,000 s/mm2 for tumor conspicuity and discrimination of aggressiveness.

PubMed

Tamada, Tsutomu; Kanomata, Naoki; Sone, Teruki; Jo, Yoshimasa; Miyaji, Yoshiyuki; Higashi, Hiroki; Yamamoto, Akira; Ito, Katsuyoshi

2014-01-01

The objective of our study was to investigate tumor conspicuity and the discrimination potential for tumor aggressiveness on diffusion-weighted magnetic resonance imaging (DW-MRI) with high b value at 3-T. The institutional review board approved this study and waived the requirement for informed consent. A total of 50 patients with prostate cancer (69 cancer foci; 48 in the PZ, 20 in the TZ, and one in whole prostate) who underwent multiparametric prostate MRI including DW-MRI (b values: 0, 1000 s/mm2 and 0, 2000 s/mm2) on a 3-T system were included. Lesion conspicuity score (LCS) using visual assessment (1 = invisible for surrounding normal site; 2 = slightly high intensity; 3 = moderately high; and 4 = very high) and tumor-normal signal intensity ratio (TNR) were assessed, and apparent diffusion coefficient (ADC, ×10-3 mm2/s) of the tumor regions and normal regions were measured. Mean LCS and TNR at 0, 2000 s/mm2 was significantly higher than those at 0, 1000 s/mm2 (p<0.001 for both). In addition, ADC at both 0, 1000 and 0, 2000 s/mm2 was found to distinguish intermediate or high risk cancer with Gleason score ≥7 from low risk cancer with Gleason score ≤6 (p<0.001 for both). Furthermore, ADC of tumor regions correlated with Gleason score at both 0, 1000 s/mm2 (ρ = -0.602; p<0.001) and 0, 2000 s/mm2 (ρ = -0.645; p<0.001). For tumor conspicuity and characterization of prostate cancer on DW-MRI of 3-T MRI, b = 0, 2000 s/mm2 is more useful than b = 0, 1000 s/mm2.

WE-G-BRD-01: Diffusion Weighted MRI for Response Assessment of Inoperable Lung Tumors for Patients Undergoing SBRT Treatment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tyagi, N; Wengler, K; Yorke, E

2014-06-15

Purpose: To investigate early changes in tumor Apparent Diffusion Coefficients derived from diffusion weighted (DW)-MRI of lung cancer patients undergoing SBRT, as a possible early predictor of treatment response. Methods: DW-MRI scans were performed in this prospective phase I IRB-approved study of inoperable lung tumors at various time-points during the course of SBRT treatments. Axial DW scan using multi b-values ranging from 0–1000 s/mm{sup 2} were acquired in treatment position on a 3T Philips MR scanner during simulation, one hour after the first fraction (8 Gy), after a total of 5 fractions (40 Gy) and 4 weeks after SBRT delivery.more » A monoexponential model based on a least square fit from all b values was performed on a pixel-by-pixel basis and ADC was calculated. GTVs drawn on 4DCT for planning were mapped on the T2w MRI (acquired at exhale) after deformable registration. These volumes were then mapped on DWI scan for ADC calculation after rigid registration between the anatomical scan and diffusion scan. T2w scan on followup time points were deformably registered to the pretreatment T2 scan. Results: The first two patients in this study were analyzed. Median ADC values were 1.48, 1.48, 1.62 and 1.83 (10{sup −3}×) mm{sup 2}/s at pretreatment, after 8 Gy, after 40 Gy and 4 weeks posttreatment for the first patient and 1.57, 1.53, 1.66 and 1.72 (10{sup −3}×) mm{sup 2}/s for the second patient. ADC increased more significantly after 4 weeks of treatment rather than immediately post treatment, implying that late ADC value may be a better predictor of tumor response for SBRT treatment. The fraction of tumor pixels at high ADC values increased at 4 weeks post treatment. Conclusion: The observed increase in ADC values before the end of radiotherapy may be a surrogate for tumor response, but further patient accrual will be necessary to determine its value.« less

Whole-body MRI including diffusion-weighted MRI compared with 5-HTP PET/CT in the detection of neuroendocrine tumors

PubMed Central

Carlbom, Lina; Caballero-Corbalán, José; Granberg, Dan; Sörensen, Jens; Eriksson, Barbro; Ahlström, Håkan

2017-01-01

Aim We wanted to explore if whole-body magnetic resonance imaging (MRI) including diffusion-weighted (DW) and liver-specific contrast agent-enhanced imaging could be valuable in lesion detection of neuroendocrine tumors (NET). [11C]-5-Hydroxytryptophan positron emission tomography/computed tomography (5-HTP PET/CT) was used for comparison. Materials and methods Twenty-one patients with NET were investigated with whole-body MRI, including DW imaging (DWI) and contrast-enhanced imaging of the liver, and whole-body 5-HTP PET/CT. Seven additional patients underwent upper abdomen MRI including DWI, liver-specific contrast agent-enhanced imaging, and 5-HTP PET/CT. Results There was a patient-based concordance of 61% and a lesion-based concordance of 53% between the modalities. MRI showed good concordance with PET in detecting bone metastases but was less sensitive in detecting metastases in mediastinal lymph nodes. MRI detected more liver metastases than 5-HTP PET/CT. Conclusion Whole-body MRI with DWI did not detect all NET lesions found with whole-body 5-HTP PET/CT. Our findings indicate that MRI of the liver including liver-specific contrast agent-enhanced imaging and DWI could be a useful complement to whole-body 5-HTP PET/CT. PMID:27894208

Registration of High Angular Resolution Diffusion MRI Images Using 4th Order Tensors⋆

PubMed Central

Barmpoutis, Angelos; Vemuri, Baba C.; Forder, John R.

2009-01-01

Registration of Diffusion Weighted (DW)-MRI datasets has been commonly achieved to date in literature by using either scalar or 2nd-order tensorial information. However, scalar or 2nd-order tensors fail to capture complex local tissue structures, such as fiber crossings, and therefore, datasets containing fiber-crossings cannot be registered accurately by using these techniques. In this paper we present a novel method for non-rigidly registering DW-MRI datasets that are represented by a field of 4th-order tensors. We use the Hellinger distance between the normalized 4th-order tensors represented as distributions, in order to achieve this registration. Hellinger distance is easy to compute, is scale and rotation invariant and hence allows for comparison of the true shape of distributions. Furthermore, we propose a novel 4th-order tensor re-transformation operator, which plays an essential role in the registration procedure and shows significantly better performance compared to the re-orientation operator used in literature for DTI registration. We validate and compare our technique with other existing scalar image and DTI registration methods using simulated diffusion MR data and real HARDI datasets. PMID:18051145

Comparison of [{sup 11}C]choline Positron Emission Tomography With T2- and Diffusion-Weighted Magnetic Resonance Imaging for Delineating Malignant Intraprostatic Lesions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chang, Joe H.; University of Melbourne, Victoria; Lim Joon, Daryl

2015-06-01

Purpose: The purpose of this study was to compare the accuracy of [{sup 11}C]choline positron emission tomography (CHOL-PET) with that of the combination of T2-weighted and diffusion-weighted (T2W/DW) magnetic resonance imaging (MRI) for delineating malignant intraprostatic lesions (IPLs) for guiding focal therapies and to investigate factors predicting the accuracy of CHOL-PET. Methods and Materials: This study included 21 patients who underwent CHOL-PET and T2W/DW MRI prior to radical prostatectomy. Two observers manually delineated IPL contours for each scan, and automatic IPL contours were generated on CHOL-PET based on varying proportions of the maximum standardized uptake value (SUV). IPLs identified onmore » prostatectomy specimens defined reference standard contours. The imaging-based contours were compared with the reference standard contours using Dice similarity coefficient (DSC), and sensitivity and specificity values. Factors that could potentially predict the DSC of the best contouring method were analyzed using linear models. Results: The best automatic contouring method, 60% of the maximum SUV (SUV{sub 60}) , had similar correlations (DSC: 0.59) with the manual PET contours (DSC: 0.52, P=.127) and significantly better correlations than the manual MRI contours (DSC: 0.37, P<.001). The sensitivity and specificity values were 72% and 71% for SUV{sub 60}; 53% and 86% for PET manual contouring; and 28% and 92% for MRI manual contouring. The tumor volume and transition zone pattern could independently predict the accuracy of CHOL-PET. Conclusions: CHOL-PET is superior to the combination of T2W/DW MRI for delineating IPLs. The accuracy of CHOL-PET is insufficient for gland-sparing focal therapies but may be accurate enough for focal boost therapies. The transition zone pattern is a new classification that may predict how well CHOL-PET delineates IPLs.« less

Characterization of diffuse orbital mass using Apparent diffusion coefficient in 3-tesla MRI.

PubMed

ElKhamary, Sahar M; Galindo-Ferreiro, Alicia; AlGhafri, Laila; Khandekar, Rajiv; Schellini, Silvana Artioli

2018-01-01

To evaluate if the apparent diffusion coefficient (ADC) value in diffusion-weighted magnetic resonance imaging (DW-MRI) improves the diagnostic accuracy of diffuse orbital masses. ADC DW-MRI was used to evaluate cases of diffuse orbital masses at our institution from 2000 to 2015. Lesions were grouped according to histopathologic diagnosis as, benign, pre-malignant and malignant. Lymphoproliferative lesions were further subgrouped as lymphoma or other lymphoproliferative lesions. The validity of the ADC value for the diffuse orbital mass was compared between groups. The area under curve (AUC) was also calculated. Thirty-nine cases of diffuse orbital masses were evaluated. The median ADC was 0.58 (25% quartile 0.48; minimum: 0.45; maximum: 1.72 × 10 (-3) ) for the malignant tumors and 1.19 (25% quartile 0.7; minimum: 0.5; maximum: 1.95 × 10 (-3)  mm (2)  s (-1) ) for benign lesions. This difference in ADC between lesions was statistically significant (Mann Whitney U test P < 0.001). The median ADC was 0.51 (25% quartile 0.48) for lymphomas and 0.9 (25% quartile 0.7) for other lymphoproliferative lesions. This difference in ADC was statistically significant (Mann Whitney U test P = 0.02). An ADC value of 0.8 × 10 (-3)  mm (2)  s (-1) was noted as the ideal threshold value for differentiating malignant from benign diffuse orbital masses. The validity of ADC in predicting a malignant or benign diffuse orbital mass had a sensitivity of 87%, specificity of 67% and accuracy of 88%. ADC is a promising imaging metric to characterize malignant and benign diffuse orbital masses and to distinguish lymphomas from other non-lymphoproliferative lesions.

Anomalous Extracellular Diffusion in Rat Cerebellum

PubMed Central

Xiao, Fanrong; Hrabe, Jan; Hrabetova, Sabina

2015-01-01

Extracellular space (ECS) is a major channel transporting biologically active molecules and drugs in the brain. Diffusion-mediated transport of these substances is hindered by the ECS structure but the microscopic basis of this hindrance is not fully understood. One hypothesis proposes that the hindrance originates in large part from the presence of dead-space (DS) microdomains that can transiently retain diffusing molecules. Because previous theoretical and modeling work reported an initial period of anomalous diffusion in similar environments, we expected that brain regions densely populated by DS microdomains would exhibit anomalous extracellular diffusion. Specifically, we targeted granular layers (GL) of rat and turtle cerebella that are populated with large and geometrically complex glomeruli. The integrative optical imaging (IOI) method was employed to evaluate diffusion of fluorophore-labeled dextran (MW 3000) in GL, and the IOI data analysis was adapted to quantify the anomalous diffusion exponent dw from the IOI records. Diffusion was significantly anomalous in rat GL, where dw reached 4.8. In the geometrically simpler turtle GL, dw was elevated but not robustly anomalous (dw = 2.6). The experimental work was complemented by numerical Monte Carlo simulations of anomalous ECS diffusion in several three-dimensional tissue models containing glomeruli-like structures. It demonstrated that both the duration of transiently anomalous diffusion and the anomalous exponent depend on the size of model glomeruli and the degree of their wrapping. In conclusion, we have found anomalous extracellular diffusion in the GL of rat cerebellum. This finding lends support to the DS microdomain hypothesis. Transiently anomalous diffusion also has a profound effect on the spatiotemporal distribution of molecules released into the ECS, especially at diffusion distances on the order of a few cell diameters, speeding up short-range diffusion-mediated signals in less permeable structures. PMID:25954895

Incentive or Habit Learning in Amphibians?

PubMed Central

Muzio, Rubén N.; Pistone Creydt, Virginia; Iurman, Mariana; Rinaldi, Mauro A.; Sirani, Bruno; Papini, Mauricio R.

2011-01-01

Toads (Rhinella arenarum) received training with a novel incentive procedure involving access to solutions of different NaCl concentrations. In Experiment 1, instrumental behavior and weight variation data confirmed that such solutions yield incentive values ranging from appetitive (deionized water, DW, leading to weight gain), to neutral (300 mM slightly hypertonic solution, leading to no net weight gain or loss), and aversive (800 mM highly hypertonic solution leading to weight loss). In Experiment 2, a downshift from DW to a 300 mM solution or an upshift from a 300 mM solution to DW led to a gradual adjustment in instrumental behavior. In Experiment 3, extinction was similar after acquisition with access to only DW or with a random mixture of DW and 300 mM. In Experiment 4, a downshift from DW to 225, 212, or 200 mM solutions led again to gradual adjustments. These findings add to a growing body of comparative evidence suggesting that amphibians adjust to incentive shifts on the basis of habit formation and reorganization. PMID:22087217

Diffusion-tensor imaging of major white matter tracts and their role in language processing in aphasia.

PubMed

Ivanova, Maria V; Isaev, Dmitry Yu; Dragoy, Olga V; Akinina, Yulia S; Petrushevskiy, Alexey G; Fedina, Oksana N; Shklovsky, Victor M; Dronkers, Nina F

2016-12-01

A growing literature is pointing towards the importance of white matter tracts in understanding the neural mechanisms of language processing, and determining the nature of language deficits and recovery patterns in aphasia. Measurements extracted from diffusion-weighted (DW) images provide comprehensive in vivo measures of local microstructural properties of fiber pathways. In the current study, we compared microstructural properties of major white matter tracts implicated in language processing in each hemisphere (these included arcuate fasciculus (AF), superior longitudinal fasciculus (SLF), inferior longitudinal fasciculus (ILF), inferior frontal-occipital fasciculus (IFOF), uncinate fasciculus (UF), and corpus callosum (CC), and corticospinal tract (CST) for control purposes) between individuals with aphasia and healthy controls and investigated the relationship between these neural indices and language deficits. Thirty-seven individuals with aphasia due to left hemisphere stroke and eleven age-matched controls were scanned using DW imaging sequences. Fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD), axial diffusivity (AD) values for each major white matter tract were extracted from DW images using tract masks chosen from standardized atlases. Individuals with aphasia were also assessed with a standardized language test in Russian targeting comprehension and production at the word and sentence level. Individuals with aphasia had significantly lower FA values for left hemisphere tracts and significantly higher values of MD, RD and AD for both left and right hemisphere tracts compared to controls, all indicating profound impairment in tract integrity. Language comprehension was predominantly related to integrity of the left IFOF and left ILF, while language production was mainly related to integrity of the left AF. In addition, individual segments of these three tracts were differentially associated with language production and comprehension in aphasia. Our findings highlight the importance of fiber pathways in supporting different language functions and point to the importance of temporal tracts in language processing, in particular, comprehension. Copyright © 2016 Elsevier Ltd. All rights reserved.

Value of diffusion-weighted MRI and apparent diffusion coefficient measurements for predicting the response of locally advanced rectal cancer to neoadjuvant chemoradiotherapy.

PubMed

Iannicelli, Elsa; Di Pietropaolo, Marco; Pilozzi, Emanuela; Osti, Mattia Falchetto; Valentino, Maria; Masoni, Luigi; Ferri, Mario

2016-10-01

The aim of our study was to assess the performance value of magnetic resonance imaging (MRI) in the restaging of locally advanced rectal cancer after neoadjuvant chemoradiotherapy (CRT) and in the identification of good vs. poor responders to neoadjuvant therapy. A total of 34 patients with locally advanced rectal cancer underwent MRI prior to and after CRT. T stage and tumor regression grade (TRG) on post-CRT MRI was compared with the pathological staging ypT and TRG. Tumor volume and the apparent diffusion coefficient (ADC) were measured using diffusion-weighted imaging (DWI) before and after neoadjuvant CRT; the percentage of tumor volume reduction and the change of ADC (ΔADC) was also calculated. ADC parameters and the percentage of tumor volume reduction were correlated to histopathological results. The diagnostic performance of ADC and volume reduction to assess tumor response was evaluated by calculating the area under the ROC curve and the optimal cut-off values. A significant correlation between the T stage and the TRG defined in DW-MRI after CRT and the ypT and the TRG observed on the surgical specimens was found (p = 0.001; p < 0.001). The mean post-CRT ADC and ΔADC in responder patients was significantly higher compared to non-responder ones (p = 0.001; p = 0.01). Furthermore, the mean post-CRT ADC values were significantly higher in tumors with T-downstage (p = 0.01). DW-MRI may have a significant role in the restaging and in the evaluation of post-CRT response of locally advanced rectal cancer. Quantitative analysis of DWI through ADC map may result in a promising noninvasive tool to evaluate the response to therapy.

Multi-Shot Sensitivity-Encoded Diffusion Data Recovery Using Structured Low-Rank Matrix Completion (MUSSELS)

PubMed Central

Mani, Merry; Jacob, Mathews; Kelley, Douglas; Magnotta, Vincent

2017-01-01

Purpose To introduce a novel method for the recovery of multi-shot diffusion weighted (MS-DW) images from echo-planar imaging (EPI) acquisitions. Methods Current EPI-based MS-DW reconstruction methods rely on the explicit estimation of the motion-induced phase maps to recover artifact-free images. In the new formulation, the k-space data of the artifact-free DWI is recovered using a structured low-rank matrix completion scheme, which does not require explicit estimation of the phase maps. The structured matrix is obtained as the lifting of the multi-shot data. The smooth phase-modulations between shots manifest as null-space vectors of this matrix, which implies that the structured matrix is low-rank. The missing entries of the structured matrix are filled in using a nuclear-norm minimization algorithm subject to the data-consistency. The formulation enables the natural introduction of smoothness regularization, thus enabling implicit motion-compensated recovery of the MS-DW data. Results Our experiments on in-vivo data show effective removal of artifacts arising from inter-shot motion using the proposed method. The method is shown to achieve better reconstruction than the conventional phase-based methods. Conclusion We demonstrate the utility of the proposed method to effectively recover artifact-free images from Cartesian fully/under-sampled and partial Fourier acquired data without the use of explicit phase estimates. PMID:27550212

Quantitative body DW-MRI biomarkers uncertainty estimation using unscented wild-bootstrap.

PubMed

Freiman, M; Voss, S D; Mulkern, R V; Perez-Rossello, J M; Warfield, S K

2011-01-01

We present a new method for the uncertainty estimation of diffusion parameters for quantitative body DW-MRI assessment. Diffusion parameters uncertainty estimation from DW-MRI is necessary for clinical applications that use these parameters to assess pathology. However, uncertainty estimation using traditional techniques requires repeated acquisitions, which is undesirable in routine clinical use. Model-based bootstrap techniques, for example, assume an underlying linear model for residuals rescaling and cannot be utilized directly for body diffusion parameters uncertainty estimation due to the non-linearity of the body diffusion model. To offset this limitation, our method uses the Unscented transform to compute the residuals rescaling parameters from the non-linear body diffusion model, and then applies the wild-bootstrap method to infer the body diffusion parameters uncertainty. Validation through phantom and human subject experiments shows that our method identify the regions with higher uncertainty in body DWI-MRI model parameters correctly with realtive error of -36% in the uncertainty values.

Whole lung morphometry with 3D multiple b-value hyperpolarized gas MRI and compressed sensing.

PubMed

Chan, Ho-Fung; Stewart, Neil J; Parra-Robles, Juan; Collier, Guilhem J; Wild, Jim M

2017-05-01

To demonstrate three-dimensional (3D) multiple b-value diffusion-weighted (DW) MRI of hyperpolarized 3 He gas for whole lung morphometry with compressed sensing (CS). A fully-sampled, two b-value, 3D hyperpolarized 3 He DW-MRI dataset was acquired from the lungs of a healthy volunteer and retrospectively undersampled in the k y and k z phase-encoding directions for CS simulations. Optimal k-space undersampling patterns were determined by minimizing the mean absolute error between reconstructed and fully-sampled 3 He apparent diffusion coefficient (ADC) maps. Prospective three-fold, undersampled, 3D multiple b-value 3 He DW-MRI datasets were acquired from five healthy volunteers and one chronic obstructive pulmonary disease (COPD) patient, and the mean values of maps of ADC and mean alveolar dimension (Lm D ) were validated against two-dimensional (2D) and 3D fully-sampled 3 He DW-MRI experiments. Reconstructed undersampled datasets showed no visual artifacts and good preservation of the main image features and quantitative information. A good agreement between fully-sampled and prospective undersampled datasets was found, with a mean difference of +3.4% and +5.1% observed in mean global ADC and Lm D values, respectively. These differences were within the standard deviation range and consistent with values reported from healthy and COPD lungs. Accelerated CS acquisition has facilitated 3D multiple b-value 3 He DW-MRI scans in a single breath-hold, enabling whole lung morphometry mapping. Magn Reson Med 77:1916-1925, 2017. © 2016 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. © 2016 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine.

Liver diffusion-weighted MR imaging: reproducibility comparison of ADC measurements obtained with multiple breath-hold, free-breathing, respiratory-triggered, and navigator-triggered techniques.

PubMed

Chen, Xin; Qin, Lei; Pan, Dan; Huang, Yanqi; Yan, Lifen; Wang, Guangyi; Liu, Yubao; Liang, Changhong; Liu, Zaiyi

2014-04-01

To prospectively compare the reproducibility of normal liver apparent diffusion coefficient (ADC) measurements by using different respiratory motion compensation techniques with multiple breath-hold (MBH), free-breathing (FB), respiratory-triggered (RT), and navigator-triggered (NT) diffusion-weighted (DW) imaging and to compare the ADCs at different liver anatomic locations. The study protocol was approved by the institutional review board, and written informed consent was obtained from each participant. Thirty-nine volunteers underwent liver DW imaging twice. Imaging was performed with a 1.5-T MR imager with MBH, FB, RT, and NT techniques (b = 0, 100, and 500 sec/mm(2)). Three representative sections--superior, central, and inferior--were selected on left and right liver lobes, respectively. On each selected section, three regions of interest were drawn, and ADCs were measured. Analysis of variance was used to assess ADCs among the four techniques and various anatomic locations. Reproducibility of ADCs was assessed with the Bland-Altman method. ADCs obtained with MBH (range: right lobe, [1.641-1.662] × 10(-3)mm(2)/sec; left lobe, [2.034-2.054] ×10(-3)mm(2)/sec) were higher than those obtained with FB (right, [1.349-1.391] ×10(-3)mm(2)/sec; left, [1.630-1.700] ×10(-3)mm(2)/sec), RT (right, [1.439-1.455] ×10(-3)mm(2)/sec; left, [1.720-1.755] ×10(-3)mm(2)/sec), or NT (right, [1.387-1.400] ×10(-3)mm(2)/sec; left, [1.661-1.736] ×10(-3)mm(2)/sec) techniques (P < .001); however, no significant difference was observed between ADCs obtained with FB, RT, and NT techniques (P = .130 to P >.99). ADCs showed a trend to decrease moving from left to right. Reproducibility in the left liver lobe was inferior to that in the right, and the central middle segment in the right lobe had the most reproducible ADC. Statistical differences in ADCs were observed in the left-right direction in the right lobe (P < .001), but they were not observed in the superior-inferior direction (P = .144-.450). However, in the left liver lobe, statistical differences existed in both directions (P = .001 to P = .016 in the left-right direction, P < .001 in the superior-inferior direction). Both anatomic location and DW imaging technique influence liver ADC measurements and their reproducibility. FB DW imaging is recommended for liver DW imaging because of its good reproducibility and shorter acquisition time compared with that of MBH, RT, and NT techniques. RSNA, 2014

Anomalous diffusion on a random comblike structure

NASA Astrophysics Data System (ADS)

Havlin, Shlomo; Kiefer, James E.; Weiss, George H.

1987-08-01

We have recently studied a random walk on a comblike structure as an analog of diffusion on a fractal structure. In our earlier work, the comb was assumed to have a deterministic structure, the comb having teeth of infinite length. In the present paper we study diffusion on a one-dimensional random comb, the length of whose teeth are random variables with an asymptotic stable law distribution φ(L)~L-(1+γ) where 0<γ<=1. Two mean-field methods are used for the analysis, one based on the continuous-time random walk, and the second a self-consistent scaling theory. Both lead to the same conclusions. We find that the diffusion exponent characterizing the mean-square displacement along the backbone of the comb is dw=4/(1+γ) for γ<1 and dw=2 for γ>=1. The probability of being at the origin at time t is P0(t)~t-ds/2 for large t with ds=(3-γ)/2 for γ<1 and ds=1 for γ>1. When a field is applied along the backbone of the comb the diffusion exponent is dw=2/(1+γ) for γ<1 and dw=1 for γ>=1. The theoretical results are confirmed using the exact enumeration method.

A Unified Approach to Diffusion Direction Sensitive Slice Registration and 3-D DTI Reconstruction From Moving Fetal Brain Anatomy

PubMed Central

Fogtmann, Mads; Seshamani, Sharmishtaa; Kroenke, Christopher; Cheng, Xi; Chapman, Teresa; Wilm, Jakob; Rousseau, François

2014-01-01

This paper presents an approach to 3-D diffusion tensor image (DTI) reconstruction from multi-slice diffusion weighted (DW) magnetic resonance imaging acquisitions of the moving fetal brain. Motion scatters the slice measurements in the spatial and spherical diffusion domain with respect to the underlying anatomy. Previous image registration techniques have been described to estimate the between slice fetal head motion, allowing the reconstruction of 3-D a diffusion estimate on a regular grid using interpolation. We propose Approach to Unified Diffusion Sensitive Slice Alignment and Reconstruction (AUDiSSAR) that explicitly formulates a process for diffusion direction sensitive DW-slice-to-DTI-volume alignment. This also incorporates image resolution modeling to iteratively deconvolve the effects of the imaging point spread function using the multiple views provided by thick slices acquired in different anatomical planes. The algorithm is implemented using a multi-resolution iterative scheme and multiple real and synthetic data are used to evaluate the performance of the technique. An accuracy experiment using synthetically created motion data of an adult head and a experiment using synthetic motion added to sedated fetal monkey dataset show a significant improvement in motion-trajectory estimation compared to a state-of-the-art approaches. The performance of the method is then evaluated on challenging but clinically typical in utero fetal scans of four different human cases, showing improved rendition of cortical anatomy and extraction of white matter tracts. While the experimental work focuses on DTI reconstruction (second-order tensor model), the proposed reconstruction framework can employ any 5-D diffusion volume model that can be represented by the spatial parameterizations of an orientation distribution function. PMID:24108711

Detection of the index tumour and tumour volume in prostate cancer using T2-weighted and diffusion-weighted magnetic resonance imaging (MRI) alone.

PubMed

Rud, Erik; Klotz, Dagmar; Rennesund, Kristin; Baco, Eduard; Berge, Viktor; Lien, Diep; Svindland, Aud; Lundeby, Eskild; Berg, Rolf E; Eri, Lars M; Eggesbø, Heidi B

2014-12-01

To examine the performance of T2-weighted (T2W) and diffusion-weighted (DW) magnetic resonance imaging (MRI) for detecting the index tumour in patients with prostate cancer and to examine the agreement between MRI and histology when assessing tumour volume (TV) and overall tumour burden. The study included 199 consecutive patients with biopsy confirmed prostate cancer randomised to MRI before radical prostatectomy from December 2009 to July 2012. MRI-detected tumours (MRTs) were ranked from 1 to 3 according to decreasing volume and were compared with histologically detected tumours (HTs) ranked from 1 to 3, with HT 1 = index tumour. Whole-mount section histology was used as a reference standard. The TVs of true-positive MRTs (MRTVs 1-3) were compared with the TVs found by histology (HTVs 1-3). All tumours were registered on a 30-sector map and by classifying each sector as positive/negative, the rate of true-positive and -negative sectors was calculated. The detection rate for the HT 1 (index tumour) was 92%; HT 2, 45%; and HT 3, 37%. The MRTV 1-3 vs the HTV 1-3 were 2.8 mL vs 4.0 mL (index tumour, P < 0.001), 1.0 mL vs 0.9 mL (tumour 2, P = 0.413), and 0.6 mL vs 0.5 mL (tumour 3, P = 0.492). The rate of true-positive and -negative sectors was 50% and 88%, κ = 0.39. A combination of T2W and DW MRI detects the index tumour in 92% of cases, although MRI underestimates both TV and tumour burden compared with histology. © 2014 The Authors. BJU International © 2014 BJU International.

78 FR 59878 - Atlantic Highly Migratory Species; Commercial Atlantic Aggregated Large Coastal Shark (LCS...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-30

... submitted electronically on a weekly basis through a NMFS-approved electronic reporting system by the dealer... metric tons (mt) dressed weight (dw) (149,914 lb dw) of non-blacknose SCS quota from the Atlantic region... lb dw), the Atlantic hammerhead shark management group quota is 27.1 metric tons (mt) dressed weight...

Anomalous extracellular diffusion in rat cerebellum.

PubMed

Xiao, Fanrong; Hrabe, Jan; Hrabetova, Sabina

2015-05-05

Extracellular space (ECS) is a major channel transporting biologically active molecules and drugs in the brain. Diffusion-mediated transport of these substances is hindered by the ECS structure but the microscopic basis of this hindrance is not fully understood. One hypothesis proposes that the hindrance originates in large part from the presence of dead-space (DS) microdomains that can transiently retain diffusing molecules. Because previous theoretical and modeling work reported an initial period of anomalous diffusion in similar environments, we expected that brain regions densely populated by DS microdomains would exhibit anomalous extracellular diffusion. Specifically, we targeted granular layers (GL) of rat and turtle cerebella that are populated with large and geometrically complex glomeruli. The integrative optical imaging (IOI) method was employed to evaluate diffusion of fluorophore-labeled dextran (MW 3000) in GL, and the IOI data analysis was adapted to quantify the anomalous diffusion exponent dw from the IOI records. Diffusion was significantly anomalous in rat GL, where dw reached 4.8. In the geometrically simpler turtle GL, dw was elevated but not robustly anomalous (dw = 2.6). The experimental work was complemented by numerical Monte Carlo simulations of anomalous ECS diffusion in several three-dimensional tissue models containing glomeruli-like structures. It demonstrated that both the duration of transiently anomalous diffusion and the anomalous exponent depend on the size of model glomeruli and the degree of their wrapping. In conclusion, we have found anomalous extracellular diffusion in the GL of rat cerebellum. This finding lends support to the DS microdomain hypothesis. Transiently anomalous diffusion also has a profound effect on the spatiotemporal distribution of molecules released into the ECS, especially at diffusion distances on the order of a few cell diameters, speeding up short-range diffusion-mediated signals in less permeable structures. Copyright © 2015 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Changes in the microarchitecture of the pancreatic cancer stroma are linked to neutrophil-dependent reprogramming of stellate cells and reflected by diffusion-weighted magnetic resonance imaging

PubMed Central

Mayer, Philipp; Dinkic, Christine; Jesenofsky, Ralf; Klauss, Miriam; Schirmacher, Peter; Dapunt, Ulrike; Hackert, Thilo; Uhle, Florian; Hänsch, G. Maria; Gaida, Matthias M.

2018-01-01

In pancreatic cancer (PDAC) intratumor infiltration of polymorphonuclear neutrophils (PMN) is associated with histologically apparent alterations of the tumor growth pattern. The aim of this study was to examine possible associations between PMN infiltration, tumor microarchitecture, and water diffusivity in diffusion-weighted magnetic resonance imaging (DW-MRI), and to further asses the underlying mechanisms. Methods: DW-MRI was performed in 33 PDAC patients prior to surgery. In parallel, tissue specimen were examined histologically for growth pattern, azurocidin-positive PMN infiltrates, and the presence of alpha-smooth muscle actin (α-SMA) and metalloproteinase 9 (MMP9)-positive myofibroblastic cells. For confirmation of the histological findings, a tissue microarray of a second cohort of patients (n=109) was prepared and examined similarly. For in vitro studies, the pancreatic stellate cell line RLT was co-cultivated either with isolated PMN, PMN-lysates, or recombinant azurocidin and characterized by Western blot, flow cytometry, and proteome profiler arrays. Results: Tumors with high PMN density showed restricted water diffusion in DW-MRI and histologic apparent alterations of the tumor microarchitecture (microglandular, micropapillary, or overall poorly differentiated growth pattern) as opposed to tumors with scattered PMN. Areas with altered growth pattern lacked α-SMA-positive myofibroblastic cells. Tissue microarrays confirmed a close association of high PMN density with alterations of the tumor microarchitecture and revealed a significant association of high PMN density with poor histologic grade of differentiation (G3). In vitro experiments provided evidence for direct effects of PMN on stellate cells, where a change to a spindle shaped cell morphology in response to PMN and to PMN-derived azurocidin was seen. Azurocidin incorporated into stellate cells, where it associated with F-actin. Down-regulation of α-SMA was seen within hours, as was activation of the p38-cofilin axis, up-regulation of MMP9, and acquisition of intracellular lipid droplets, which together indicate a phenotype switch of the stellate cells. Conclusion: In PDAC, PMN infiltrates are associated with alterations of the tumor microarchitecture. As a causal relationship, we propose a reprogramming of stellate cells by PMN-derived azurocidin towards a phenotype, which affects the microarchitecture of the tumor. PMID:29290790

T2-weighted MRI-derived textural features reflect prostate cancer aggressiveness: preliminary results.

PubMed

Nketiah, Gabriel; Elschot, Mattijs; Kim, Eugene; Teruel, Jose R; Scheenen, Tom W; Bathen, Tone F; Selnæs, Kirsten M

2017-07-01

To evaluate the diagnostic relevance of T2-weighted (T2W) MRI-derived textural features relative to quantitative physiological parameters derived from diffusion-weighted (DW) and dynamic contrast-enhanced (DCE) MRI in Gleason score (GS) 3+4 and 4+3 prostate cancers. 3T multiparametric-MRI was performed on 23 prostate cancer patients prior to prostatectomy. Textural features [angular second moment (ASM), contrast, correlation, entropy], apparent diffusion coefficient (ADC), and DCE pharmacokinetic parameters (K trans and V e ) were calculated from index tumours delineated on the T2W, DW, and DCE images, respectively. The association between the textural features and prostatectomy GS and the MRI-derived parameters, and the utility of the parameters in differentiating between GS 3+4 and 4+3 prostate cancers were assessed statistically. ASM and entropy correlated significantly (p < 0.05) with both GS and median ADC. Contrast correlated moderately with median ADC. The textural features correlated insignificantly with K trans and V e . GS 4+3 cancers had significantly lower ASM and higher entropy than 3+4 cancers, but insignificant differences in median ADC, K trans , and V e . The combined texture-MRI parameters yielded higher classification accuracy (91%) than the individual parameter sets. T2W MRI-derived textural features could serve as potential diagnostic markers, sensitive to the pathological differences in prostate cancers. • T2W MRI-derived textural features correlate significantly with Gleason score and ADC. • T2W MRI-derived textural features differentiate Gleason score 3+4 from 4+3 cancers. • T2W image textural features could augment tumour characterization.

TU-H-CAMPUS-IeP2-01: Quantitative Evaluation of PROPELLER DWI Using QIBA Diffusion Phantom

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yung, J; Ai, H; Liu, H

Purpose: The purpose of this study is to determine the quantitative variability of apparent diffusion coefficient (ADC) values when varying imaging parameters in a diffusion-weighted (DW) fast spin echo (FSE) sequence with Periodically Rotated Overlapping ParallEL Lines with Enhanced Reconstruction (PROPELLER) k-space trajectory. Methods: Using a 3T MRI scanner, a NIST traceable, quantitative magnetic resonance imaging (MRI) diffusion phantom (High Precision Devices, Inc, Boulder, Colorado) consisting of 13 vials filled with various concentrations of polymer polyvinylpyrrolidone (PVP) in aqueous solution was imaged with a standard Quantitative Imaging Biomarkers Alliance (QIBA) DWI spin echo, echo planar imaging (SE EPI) acquisition. Themore » same phantom was then imaged with a DWI PROPELLER sequence at varying echo train lengths (ETL) of 8, 20, and 32, as well as b-values of 400, 900, and 2000. QIBA DWI phantom analysis software was used to generate ADC maps and create region of interests (ROIs) for quantitative measurements of each vial. Mean and standard deviations of the ROIs were compared. Results: The SE EPI sequence generated ADC values that showed very good agreement with the known ADC values of the phantom (r2 = 0.9995, slope = 1.0061). The ADC values measured from the PROPELLER sequences were inflated, but were highly correlated with an r2 range from 0.8754 to 0.9880. The PROPELLER sequence with an ETL=20 and b-value of 0 and 2000 showed the closest agreement (r2 = 0.9034, slope = 0.9880). Conclusion: The DW PROPELLER sequence is promising for quantitative evaluation of ADC values. A drawback of the PROPELLER sequence is the longer acquisition time. The 180° refocusing pulses may also cause the observed increase in ADC values compared to the standard SE EPI DW sequence. However, the FSE sequence offers an advantage with in-plane motion and geometric distortion which will be investigated in future studies.« less

Effect of Change in Fluid Status Evaluated by Bioimpedance Techniques on Body Composition in Hemodialysis Patients.

PubMed

Abbas, Samer R; Thijssen, Stephan; Penne, Erik L; Raimann, Jochen G; Liu, Li; Sipahioglu, Murat H; Seibert, Eric; Wang, Yuedong; Chen, Yuqi; Xiao, Qingqing; Levin, Nathan W; Kotanko, Peter; Zhu, Fansan

2018-05-01

This prospective study uses calf bioimpedance spectroscopy (cBIS) to guide the attainment of dry weight (DW cBIS ) in chronic hemodialysis (HD) patients. The primary aim of this study was to evaluate whether body composition is altered when fluid status is reduced to DW cBIS . Target post-HD weight was gradually reduced from baseline (BL) until DW cBIS was achieved. DW cBIS was defined as the presence of both flattening of the curve of extracellular resistance and the attainment calf normalized resistivity in the normal range during the dialysis treatment. Extracellular volume (ECV), intracellular volume, and total body water (TBW) were measured using whole body BIS (Hydra 4200). Fluid overload, lean body mass, and fat mass were calculated according to a body composition model. Seventy-three patients enrolled and 60 completed the study (55 ± 13 years, 49% male). Twenty-eight patients (25% diabetes) achieved DW cBIS , whereas 32 patients (47% diabetes) did not. Number of treatment measurements were 16 ± 10 and 12 ± 13 studies per patient in the DW cBIS and non-DW cBIS groups, respectively. Although significant decreases in body weight and ECV were observed, lean body mass and FM did not differ significantly in both groups from BL to the end of study. ECV, ECV/TBW, and fluid overload were higher in the non-DW cBIS than in the DW cBIS group both at BL and at the end of study. Ratios of intradialytic changes in calf normalized resistivity, ECV, and ECV/TBW to ultrafiltration volume were significantly lower in diabetic than in non-diabetic patients. This study shows that decreasing fluid status by gradual reduction of post-HD weight in both DW cBIS and Non-DW cBIS groups did not affect body composition significantly over a period of about 4 weeks. Copyright © 2017 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

DW-MRI as a Predictive Biomarker of Radiosensitization of GBM through Targeted Inhibition of Checkpoint Kinases.

PubMed

Williams, Terence M; Galbán, Stefanie; Li, Fei; Heist, Kevin A; Galbán, Craig J; Lawrence, Theodore S; Holland, Eric C; Thomae, Tami L; Chenevert, Thomas L; Rehemtulla, Alnawaz; Ross, Brian D

2013-04-01

The inherent treatment resistance of glioblastoma (GBM) can involve multiple mechanisms including checkpoint kinase (Chk1/2)-mediated increased DNA repair capability, which can attenuate the effects of genotoxic chemotherapies and radiation. The goal of this study was to evaluate diffusion-weighted magnetic resonance imaging (DW-MRI) as a biomarker for Chk1/2 inhibitors in combination with radiation for enhancement of treatment efficacy in GBM. We evaluated a specific small molecule inhibitor of Chk1/2, AZD7762, in combination with radiation using in vitro human cell lines and in vivo using a genetically engineered GBM mouse model. DW-MRI and T1-contrast MRI were used to follow treatment effects on intracranial tumor cellularity and growth rates, respectively. AZD7762 inhibited clonal proliferation in a panel of GBM cell lines and increased radiosensitivity in p53-mutated GBM cell lines to a greater extent compared to p53 wild-type cells. In vivo efficacy of AZD7762 demonstrated a dose-dependent inhibitory effect on GBM tumor growth rate and a reduction in tumor cellularity based on DW-MRI scans along with enhancement of radiation efficacy. DW-MRI was found to be a useful imaging biomarker for the detection of radiosensitization through inhibition of checkpoint kinases. Chk1/2 inhibition resulted in antiproliferative activity, prevention of DNA damage-induced repair, and radiosensitization in preclinical GBM tumor models, both in vitro and in vivo. The effects were found to be maximal in p53-mutated GBM cells. These results provide the rationale for integration of DW-MRI in clinical translation of Chk1/2 inhibition with radiation for the treatment of GBM.

Prospective comparison of 68Ga-PSMA PET/CT, 18F-sodium fluoride PET/CT and diffusion weighted-MRI at for the detection of bone metastases in biochemically recurrent prostate cancer.

PubMed

Zacho, Helle D; Nielsen, Julie B; Afshar-Oromieh, Ali; Haberkorn, Uwe; deSouza, Nandita; De Paepe, Katja; Dettmann, Katja; Langkilde, Niels C; Haarmark, Christian; Fisker, Rune V; Arp, Dennis T; Carl, Jesper; Jensen, Jørgen B; Petersen, Lars J

2018-06-06

To prospectively compare diagnostic accuracies for detection of bone metastases by 68 Ga-PSMA PET/CT, 18 F-NaF PET/CT and diffusion-weighted MRI (DW 600 -MRI) in prostate cancer (PCa) patients with biochemical recurrence (BCR). Sixty-eight PCa patients with BCR participated in this prospective study. The patients underwent 68 Ga-PSMA PET/CT, a 18 F-NaF PET/CT and a DW 600 -MRI (performed in accordance with European Society of Urogenital Radiology guidelines, with b values of 0 and 600 s/mm 2 ). Bone lesions were categorized using a three-point scale (benign, malignant or equivocal for metastases) and a dichotomous scale (benign or metastatic) for each imaging modality by at least two experienced observers. A best valuable comparator was defined for each patient based on study-specific imaging, at least 12 months of clinical follow-up and any imaging prior to the study and during follow-up. Diagnostic performance was assessed using a sensitivity analysis where equivocal lesions were handled as non-metastatic and then as metastatic. Ten of the 68 patients were diagnosed with bone metastases. On a patient level, sensitivity, specificity and the area under the curve (AUC) by receiver operating characteristic analysis were, respectively, 0.80, 0.98-1.00 and 0.89-0.90 for 68 Ga-PSMA PET/CT (n = 68 patients); 0.90, 0.90-0.98 and 0.90-0.94 for 18 NaF PET/CT (n = 67 patients); and 0.25-0.38, 0.87-0.92 and 0.59-0.62 for DW 600 -MRI (n = 60 patients). The diagnostic performance of DW 600 -MRI was significantly lower than that of 68 Ga-PSMA PET/CT and 18 NaF PET/CT for diagnosing bone metastases (p < 0.01), and no significant difference in the AUC was seen between 68 Ga-PSMA PET/CT and 18 NaF PET/CT (p = 0.65). 68 Ga-PSMA PET/CT and 18 F-NaF PET/CT showed comparable and high diagnostic accuracies for detecting bone metastases in PCa patients with BCR. Both methods performed significantly better than DW 600 -MRI, which was inadequate for diagnosing bone metastases when conducted in accordance with European Society of Urogenital Radiology guidelines.

Localized Statistics for DW-MRI Fiber Bundle Segmentation

PubMed Central

Lankton, Shawn; Melonakos, John; Malcolm, James; Dambreville, Samuel; Tannenbaum, Allen

2013-01-01

We describe a method for segmenting neural fiber bundles in diffusion-weighted magnetic resonance images (DWMRI). As these bundles traverse the brain to connect regions, their local orientation of diffusion changes drastically, hence a constant global model is inaccurate. We propose a method to compute localized statistics on orientation information and use it to drive a variational active contour segmentation that accurately models the non-homogeneous orientation information present along the bundle. Initialized from a single fiber path, the proposed method proceeds to capture the entire bundle. We demonstrate results using the technique to segment the cingulum bundle and describe several extensions making the technique applicable to a wide range of tissues. PMID:23652079

Diffusion MRI microstructure models with in vivo human brain Connectome data: results from a multi-group comparison.

PubMed

Ferizi, Uran; Scherrer, Benoit; Schneider, Torben; Alipoor, Mohammad; Eufracio, Odin; Fick, Rutger H J; Deriche, Rachid; Nilsson, Markus; Loya-Olivas, Ana K; Rivera, Mariano; Poot, Dirk H J; Ramirez-Manzanares, Alonso; Marroquin, Jose L; Rokem, Ariel; Pötter, Christian; Dougherty, Robert F; Sakaie, Ken; Wheeler-Kingshott, Claudia; Warfield, Simon K; Witzel, Thomas; Wald, Lawrence L; Raya, José G; Alexander, Daniel C

2017-09-01

A large number of mathematical models have been proposed to describe the measured signal in diffusion-weighted (DW) magnetic resonance imaging (MRI). However, model comparison to date focuses only on specific subclasses, e.g. compartment models or signal models, and little or no information is available in the literature on how performance varies among the different types of models. To address this deficiency, we organized the 'White Matter Modeling Challenge' during the International Symposium on Biomedical Imaging (ISBI) 2015 conference. This competition aimed to compare a range of different kinds of models in their ability to explain a large range of measurable in vivo DW human brain data. Specifically, we assessed the ability of models to predict the DW signal accurately for new diffusion gradients and b values. We did not evaluate the accuracy of estimated model parameters, as a ground truth is hard to obtain. We used the Connectome scanner at the Massachusetts General Hospital, using gradient strengths of up to 300 mT/m and a broad set of diffusion times. We focused on assessing the DW signal prediction in two regions: the genu in the corpus callosum, where the fibres are relatively straight and parallel, and the fornix, where the configuration of fibres is more complex. The challenge participants had access to three-quarters of the dataset and their models were ranked on their ability to predict the remaining unseen quarter of the data. The challenge provided a unique opportunity for a quantitative comparison of diverse methods from multiple groups worldwide. The comparison of the challenge entries reveals interesting trends that could potentially influence the next generation of diffusion-based quantitative MRI techniques. The first is that signal models do not necessarily outperform tissue models; in fact, of those tested, tissue models rank highest on average. The second is that assuming a non-Gaussian (rather than purely Gaussian) noise model provides little improvement in prediction of unseen data, although it is possible that this may still have a beneficial effect on estimated parameter values. The third is that preprocessing the training data, here by omitting signal outliers, and using signal-predicting strategies, such as bootstrapping or cross-validation, could benefit the model fitting. The analysis in this study provides a benchmark for other models and the data remain available to build up a more complete comparison in the future. Copyright © 2017 The Authors. NMR in Biomedicine Published by John Wiley & Sons, Ltd.

Added value of high-b-value (b = 3000 s/mm2) diffusion-weighted imaging at 3 T in relation to fluid-attenuated inversion recovery images for the evaluation of cortical lesions in inflammatory brain diseases.

PubMed

Iwashita, Koya; Hirai, Toshinori; Kitajima, Mika; Shigematsu, Yoshinori; Uetani, Hiroyuki; Iryo, Yasuhiko; Azuma, Minako; Hayashida, Eri; Ando, Yukio; Murakami, Ryuji; Yamashita, Yasuyuki

2013-01-01

The purpose of this study was to determine how the gray-to-white matter contrast in healthy subjects changes on high-b-value diffusion-weighted imaging (DWI) acquired at 3 T and evaluate whether high-b-value DWI at 3 T is useful for the detection of cortical lesions in inflammatory brain diseases. Ten healthy volunteers underwent DWI at b = 1000, 2000, 3000, 4000, and 5000 s/mm(2) on a 3-T MRI unit. On DW images, 1 radiologist performed region-of-interest measurements of the signal intensity of 8 gray matter structures. The gray-to-white matter contrast ratio (GWCR) was calculated. Ten patients with inflammatory cortical lesions were also included. All patients underwent conventional MRI and DWI at b = 1000 and 3000 s/mm(2). Using a 4-point grading system, 2 radiologists independently assessed the presence of additional information on DW images compared with fluid-attenuated inversion recovery images. Interobserver agreement was assessed by κ statistics. In the healthy subjects, the b value increased as the GWCR decreased in all evaluated gray matter structures. On DW images acquired at b = 3000 s/mm(2), mean GWCR was less than 1.0 in 7 of 8 structures. For both reviewers, DWI at b = 3000 s/mm(2) yielded significantly more additional information than did DWI at b = 1000 s/mm(2) (P < 0.05). Interobserver agreement for DWI at b = 1000 s/mm(2) and b = 3000 s/mm(2) was fair (κ = 0.35) and excellent (κ = 1.0), respectively. At 3-T DWI, the gray-to-white matter contrast in most gray matter structures reverses at b = 3000 s/mm. In the evaluation of cortical lesions in patients with inflammatory brain diseases, 3-T DWI at b = 3000 s/mm was more useful than b = 1000 s/mm(2).

Measurement of diffusion coefficients of parabens and steroids in water and 1-octanol.

PubMed

Seki, Toshinobu; Mochida, Junko; Okamoto, Maiko; Hosoya, Osamu; Juni, Kazuhiko; Morimoto, Kazuhiro

2003-06-01

Diffusion coefficients (D) of parabens and steroids in water and 1-octanol were determined by using the chromatographic broadening method at 37 degrees C, and the relationships between the D values and the physicochemical properties of the drugs were discussed. The D values in 1-octanol were lower than those in water because of the higher viscosity of 1-octanol. The D values depend on not only the molecular weight (MW), but also the lipophilicity of the drugs in water and on the ability for hydrogen-bonding in 1-octanol. When the lipophilic index (LI), calculated from the retention time using in a reverse-phase column, was used as a parameter of drug lipophilicity, the following equation was obtained for D in water (D(w)); log D(w)=-0.215.log MW-0.077.log LI-4.367. When the hydrogen bond index (HI), the logarithm of the ratio of the partition coefficient of the drugs in 1-octanol and cyclohexane, was used as an index of hydrogen-bonding, the following equation was obtained for D in 1-octanol (D(o)); log D(o)=-0.690.log MW-0.074.log HI-4.085.

Varying plant density and harvest time to optimize cowpea leaf yield and nutrient content

NASA Technical Reports Server (NTRS)

Ohler, T. A.; Nielsen, S. S.; Mitchell, C. A.

1996-01-01

Plant density and harvest time were manipulated to optimize vegetative (foliar) productivity of cowpea [Vigna unguiculata (L.) Walp.] canopies for future dietary use in controlled ecological life-support systems as vegetables or salad greens. Productivity was measured as total shoot and edible dry weights (DW), edible yield rate [(EYR) grams DW per square meter per day], shoot harvest index [(SHI) grams DW per edible gram DW total shoot], and yield-efficiency rate [(YER) grams DW edible per square meter per day per grams DW nonedible]. Cowpeas were grown in a greenhouse for leaf-only harvest at 14, 28, 42, 56, 84, or 99 plants/m2 and were harvested 20, 30, 40, or 50 days after planting (DAP). Shoot and edible dry weights increased as plant density and time to harvest increased. A maximum of 1189 g shoot DW/m2 and 594 g edible DW/m2 were achieved at an estimated plant density of 85 plants/m2 and harvest 50 DAP. EYR also increased as plant density and time to harvest increased. An EYR of 11 g m-2 day-1 was predicted to occur at 86 plants/m2 and harvest 50 DAP. SHI and YER were not affected by plant density. However, the highest values of SHI (64%) and YER (1.3 g m-2 day-1 g-1) were attained when cowpeas were harvested 20 DAP. The average fat and ash contents [dry-weight basis (dwb)] of harvested leaves remained constant regardless of harvest time. Average protein content increased from 25% DW at 30 DAP to 45% DW at 50 DAP. Carbohydrate content declined from 50% DW at 30 DAP to 45% DW at 50 DAP. Total dietary fiber content (dwb) of the leaves increased from 19% to 26% as time to harvest increased from 20 to 50 days.

Periventricular Nodular Heterotopia: Detection of Abnormal Microanatomic Fiber Structures with Whole-Brain Diffusion MR Imaging Tractography.

PubMed

Farquharson, Shawna; Tournier, J-Donald; Calamante, Fernando; Mandelstam, Simone; Burgess, Rosemary; Schneider, Michal E; Berkovic, Samuel F; Scheffer, Ingrid E; Jackson, Graeme D; Connelly, Alan

2016-12-01

Purpose To investigate whether it is possible in patients with periventricular nodular heterotopia (PVNH) to detect abnormal fiber projections that have only previously been reported in the histopathology literature. Materials and Methods Whole-brain diffusion-weighted (DW) imaging data from 14 patients with bilateral PVNH and 14 age- and sex-matched healthy control subjects were prospectively acquired by using 3.0-T magnetic resonance (MR) imaging between August 1, 2008, and December 5, 2012. All participants provided written informed consent. The DW imaging data were processed to generate whole-brain constrained spherical deconvolution (CSD)-based tractography data and super-resolution track-density imaging (TDI) maps. The tractography data were overlaid on coregistered three-dimensional T1-weighted images to visually assess regions of heterotopia. A panel of MR imaging researchers independently assessed each case and indicated numerically (no = 1, yes = 2) as to the presence of abnormal fiber tracks in nodular tissue. The Fleiss κ statistical measure was applied to assess the reader agreement. Results Abnormal fiber tracks emanating from one or more regions of heterotopia were reported by all four readers in all 14 patients with PVNH (Fleiss κ = 1). These abnormal structures were not visible on the tractography data from any of the control subjects and were not discernable on the conventional T1-weighted images of the patients with PVNH. Conclusion Whole-brain CSD-based fiber tractography and super-resolution TDI mapping reveals abnormal fiber projections in nodular tissue suggestive of abnormal organization of white matter (with abnormal fibers both within nodules and projecting to the surrounding white matter) in patients with bilateral PVNH. © RSNA, 2016.

Raman Spectroscopy of Isotopic Water Diffusion in Ultraviscous, Glassy, and Gel States in Aerosol by Use of Optical Tweezers.

PubMed

Davies, James F; Wilson, Kevin R

2016-02-16

The formation of ultraviscous, glassy, and amorphous gel states in aqueous aerosol following the loss of water results in nonequilibrium dynamics due to the extended time scales for diffusive mixing. Existing techniques for measuring water diffusion by isotopic exchange are limited by contact of samples with the substrate, and methods applied to infer diffusion coefficients from mass transport in levitated droplets requires analysis by complex coupled differential equations to derive diffusion coefficients. We present a new technique that combines contactless levitation with aerosol optical tweezers with isotopic exchange (D2O/H2O) to measure the water diffusion coefficient over a broad range (Dw ≈ 10(-12)-10(-17) m(2)·s(-1)) in viscous organic liquids (citric acid, sucrose, and shikimic acid) and inorganic gels (magnesium sulfate, MgSO4). For the organic liquids in binary and ternary mixtures, Dw depends on relative humidity and follows a simple compositional Vignes relationship. In MgSO4 droplets, water diffusivity decreases sharply with water activity and is consistent with predictions from percolation theory. These measurements show that, by combining micrometer-sized particle levitation (a contactless measurement with rapid mixing times) with an established probe of water diffusion, Dw can be simply and directly quantified for amorphous and glassy states that are inaccessible to existing methods.

The change in the diffusion of water in normal and degenerative lumbar intervertebral discs following joint mobilization compared to prone lying.

PubMed

Beattie, Paul F; Donley, Jonathan W; Arnot, Cathy F; Miller, Ronald

2009-01-01

Prospective, repeated measures obtained under treatment and control conditions. The purposes of this study were to provide preliminary evidence regarding the immediate change in the diffusion of water in the nuclear region of normal and degenerative lumbar intervertebral discs (IVDs) following a single session of lumbar joint mobilization, and to compare these findings to the immediate change in the diffusion of water following a 10-minute session of prone lying. There is conflicting evidence regarding the effectiveness and efficacy of lumbar joint mobilization. Increased knowledge of the physiologic effects of lumbar joint mobilization can lead to refinement of its clinical application. A total of 24 people (15 males and 9 females), ranging in age from 22 to 58 years, participated in this study. All subjects had a history of activity-limiting low back pain. Diffusion-weighted magnetic resonance images (DW-MRIs) were obtained immediately before and after a 10-minute session of lumbar joint mobilization. At least 1 month later, a second session was performed in which DW-MRIs were obtained immediately before and after a 10-minute session of prone lying. Following lumbar joint mobilization, a significant increase (P = .002) in the mean values for diffusion of water was observed within degenerative IVDs at L5-S1 (22.2% increase; effect size, 0.97). Degenerative IVDs at L1-2 to L4-5 and normal IVDs at L1-2 to L5-S1 did not demonstrate a change in diffusion following joint mobilization. Prone lying was not associated with a change in diffusion for normal or degenerative IVDs. The stimulus provided by lumbar joint mobilization may influence the diffusion of water in degenerative IVDs at L5-S1; however, these are preliminary findings and the relationship of these findings to pain and function needs further investigation.

Mapping the parameter space of a T2-dependent model of water diffusion MR in brain tissue.

PubMed

Hansen, Brian; Vestergaard-Poulsen, Peter

2006-10-01

We present a new model for describing the diffusion-weighted (DW) proton nuclear magnetic resonance signal obtained from normal grey matter. Our model is analytical and, in some respects, is an extension of earlier model schemes. We model tissue as composed of three separate compartments with individual properties of diffusion and transverse relaxation. Our study assumes slow exchange between compartments. We attempt to take cell morphology into account, along with its effect on water diffusion in tissues. Using this model, we simulate diffusion-sensitive MR signals and compare model output to experimental data from human grey matter. In doing this comparison, we perform a global search for good fits in the parameter space of the model. The characteristic nonmonoexponential behavior of the signal as a function of experimental b value is reproduced quite well, along with established values for tissue-specific parameters such as volume fraction, tortuosity and apparent diffusion coefficient. We believe that the presented approach to modeling diffusion in grey matter adds new aspects to the treatment of a longstanding problem.

Correction of Gradient Nonlinearity Bias in Quantitative Diffusion Parameters of Renal Tissue with Intra Voxel Incoherent Motion.

PubMed

Malyarenko, Dariya I; Pang, Yuxi; Senegas, Julien; Ivancevic, Marko K; Ross, Brian D; Chenevert, Thomas L

2015-12-01

Spatially non-uniform diffusion weighting bias due to gradient nonlinearity (GNL) causes substantial errors in apparent diffusion coefficient (ADC) maps for anatomical regions imaged distant from magnet isocenter. Our previously-described approach allowed effective removal of spatial ADC bias from three orthogonal DWI measurements for mono-exponential media of arbitrary anisotropy. The present work evaluates correction feasibility and performance for quantitative diffusion parameters of the two-component IVIM model for well-perfused and nearly isotropic renal tissue. Sagittal kidney DWI scans of a volunteer were performed on a clinical 3T MRI scanner near isocenter and offset superiorly. Spatially non-uniform diffusion weighting due to GNL resulted both in shift and broadening of perfusion-suppressed ADC histograms for off-center DWI relative to unbiased measurements close to isocenter. Direction-average DW-bias correctors were computed based on the known gradient design provided by vendor. The computed bias maps were empirically confirmed by coronal DWI measurements for an isotropic gel-flood phantom. Both phantom and renal tissue ADC bias for off-center measurements was effectively removed by applying pre-computed 3D correction maps. Comparable ADC accuracy was achieved for corrections of both b -maps and DWI intensities in presence of IVIM perfusion. No significant bias impact was observed for IVIM perfusion fraction.

Correction of Gradient Nonlinearity Bias in Quantitative Diffusion Parameters of Renal Tissue with Intra Voxel Incoherent Motion

PubMed Central

Malyarenko, Dariya I.; Pang, Yuxi; Senegas, Julien; Ivancevic, Marko K.; Ross, Brian D.; Chenevert, Thomas L.

2015-01-01

Spatially non-uniform diffusion weighting bias due to gradient nonlinearity (GNL) causes substantial errors in apparent diffusion coefficient (ADC) maps for anatomical regions imaged distant from magnet isocenter. Our previously-described approach allowed effective removal of spatial ADC bias from three orthogonal DWI measurements for mono-exponential media of arbitrary anisotropy. The present work evaluates correction feasibility and performance for quantitative diffusion parameters of the two-component IVIM model for well-perfused and nearly isotropic renal tissue. Sagittal kidney DWI scans of a volunteer were performed on a clinical 3T MRI scanner near isocenter and offset superiorly. Spatially non-uniform diffusion weighting due to GNL resulted both in shift and broadening of perfusion-suppressed ADC histograms for off-center DWI relative to unbiased measurements close to isocenter. Direction-average DW-bias correctors were computed based on the known gradient design provided by vendor. The computed bias maps were empirically confirmed by coronal DWI measurements for an isotropic gel-flood phantom. Both phantom and renal tissue ADC bias for off-center measurements was effectively removed by applying pre-computed 3D correction maps. Comparable ADC accuracy was achieved for corrections of both b-maps and DWI intensities in presence of IVIM perfusion. No significant bias impact was observed for IVIM perfusion fraction. PMID:26811845

Diffusion Tensor Magnetic Resonance Imaging Strategies for Color Mapping of Human Brain Anatomy

PubMed Central

Boujraf, Saïd

2018-01-01

Background: A color mapping of fiber tract orientation using diffusion tensor imaging (DTI) can be prominent in clinical practice. The goal of this paper is to perform a comparative study of visualized diffusion anisotropy in the human brain anatomical entities using three different color-mapping techniques based on diffusion-weighted imaging (DWI) and DTI. Methods: The first technique is based on calculating a color map from DWIs measured in three perpendicular directions. The second technique is based on eigenvalues derived from the diffusion tensor. The last technique is based on three eigenvectors corresponding to sorted eigenvalues derived from the diffusion tensor. All magnetic resonance imaging measurements were achieved using a 1.5 Tesla Siemens Vision whole body imaging system. A single-shot DW echoplanar imaging sequence used a Stejskal–Tanner approach. Trapezoidal diffusion gradients are used. The slice orientation was transverse. The basic measurement yielded a set of 13 images. Each series consists of a single image without diffusion weighting, besides two DWIs for each of the next six noncollinear magnetic field gradient directions. Results: The three types of color maps were calculated consequently using the DWI obtained and the DTI. Indeed, we established an excellent similarity between the image data in the color maps and the fiber directions of known anatomical structures (e.g., corpus callosum and gray matter). Conclusions: In the meantime, rotationally invariant quantities such as the eigenvectors of the diffusion tensor reflected better, the real orientation found in the studied tissue. PMID:29928631

Anomalous Diffusion Measured by a Twice-Refocused Spin Echo Pulse Sequence: Analysis Using Fractional Order Calculus

PubMed Central

2011-01-01

Purpose To theoretically develop and experimentally validate a formulism based on a fractional order calculus (FC) diffusion model to characterize anomalous diffusion in brain tissues measured with a twice-refocused spin-echo (TRSE) pulse sequence. Materials and Methods The FC diffusion model is the fractional order generalization of the Bloch-Torrey equation. Using this model, an analytical expression was derived to describe the diffusion-induced signal attenuation in a TRSE pulse sequence. To experimentally validate this expression, a set of diffusion-weighted (DW) images was acquired at 3 Tesla from healthy human brains using a TRSE sequence with twelve b-values ranging from 0 to 2,600 s/mm2. For comparison, DW images were also acquired using a Stejskal-Tanner diffusion gradient in a single-shot spin-echo echo planar sequence. For both datasets, a Levenberg-Marquardt fitting algorithm was used to extract three parameters: diffusion coefficient D, fractional order derivative in space β, and a spatial parameter μ (in units of μm). Using adjusted R-squared values and standard deviations, D, β and μ values and the goodness-of-fit in three specific regions of interest (ROI) in white matter, gray matter, and cerebrospinal fluid were evaluated for each of the two datasets. In addition, spatially resolved parametric maps were assessed qualitatively. Results The analytical expression for the TRSE sequence, derived from the FC diffusion model, accurately characterized the diffusion-induced signal loss in brain tissues at high b-values. In the selected ROIs, the goodness-of-fit and standard deviations for the TRSE dataset were comparable with the results obtained from the Stejskal-Tanner dataset, demonstrating the robustness of the FC model across multiple data acquisition strategies. Qualitatively, the D, β, and μ maps from the TRSE dataset exhibited fewer artifacts, reflecting the improved immunity to eddy currents. Conclusion The diffusion-induced signal attenuation in a TRSE pulse sequence can be described by an FC diffusion model at high b-values. This model performs equally well for data acquired from the human brain tissues with a TRSE pulse sequence or a conventional Stejskal-Tanner sequence. PMID:21509877

Anomalous diffusion measured by a twice-refocused spin echo pulse sequence: analysis using fractional order calculus.

PubMed

Gao, Qing; Srinivasan, Girish; Magin, Richard L; Zhou, Xiaohong Joe

2011-05-01

To theoretically develop and experimentally validate a formulism based on a fractional order calculus (FC) diffusion model to characterize anomalous diffusion in brain tissues measured with a twice-refocused spin-echo (TRSE) pulse sequence. The FC diffusion model is the fractional order generalization of the Bloch-Torrey equation. Using this model, an analytical expression was derived to describe the diffusion-induced signal attenuation in a TRSE pulse sequence. To experimentally validate this expression, a set of diffusion-weighted (DW) images was acquired at 3 Tesla from healthy human brains using a TRSE sequence with twelve b-values ranging from 0 to 2600 s/mm(2). For comparison, DW images were also acquired using a Stejskal-Tanner diffusion gradient in a single-shot spin-echo echo planar sequence. For both datasets, a Levenberg-Marquardt fitting algorithm was used to extract three parameters: diffusion coefficient D, fractional order derivative in space β, and a spatial parameter μ (in units of μm). Using adjusted R-squared values and standard deviations, D, β, and μ values and the goodness-of-fit in three specific regions of interest (ROIs) in white matter, gray matter, and cerebrospinal fluid, respectively, were evaluated for each of the two datasets. In addition, spatially resolved parametric maps were assessed qualitatively. The analytical expression for the TRSE sequence, derived from the FC diffusion model, accurately characterized the diffusion-induced signal loss in brain tissues at high b-values. In the selected ROIs, the goodness-of-fit and standard deviations for the TRSE dataset were comparable with the results obtained from the Stejskal-Tanner dataset, demonstrating the robustness of the FC model across multiple data acquisition strategies. Qualitatively, the D, β, and μ maps from the TRSE dataset exhibited fewer artifacts, reflecting the improved immunity to eddy currents. The diffusion-induced signal attenuation in a TRSE pulse sequence can be described by an FC diffusion model at high b-values. This model performs equally well for data acquired from the human brain tissues with a TRSE pulse sequence or a conventional Stejskal-Tanner sequence. Copyright © 2011 Wiley-Liss, Inc.

WE-G-18C-09: Separating Perfusion and Diffusion Components From Diffusion Weighted MRI of Rectum Tumors Based On Intravoxel Incoherent Motion (IVIM) Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tyagi, N; Wengler, K; Mazaheri, Y

2014-06-15

Purpose: Pseudodiffusion arises from the microcirculation of blood in the randomly oriented capillary network and contributes to the signal decay acquired using a multi-b value diffusion weighted (DW)-MRI sequence. This effect is more significant at low b-values and should be properly accounted for in apparent diffusion coefficient (ADC) calculations. The purpose of this study was to separate perfusion and diffusion component based on a biexponential and a segmented monoexponential model using IVIM analysis Methods. The signal attenuation is modeled as S(b) = S0[(1−f)exp(−bD) + fexp(−bD*)]. Fitting the biexponetial decay leads to the quantification of D, the true diffusion coefficient, D*,more » the pseudodiffusion coefficient, and f, the perfusion fraction. A nonlinear least squares fit and two segmented monoexponential models were used to derive the values for D, D*,‘and f. In the segmented approach b = 200 s/mm{sup 2} was used as the cut-off value for calculation of D. DW-MRI's of a rectum cancer patient were acquired before chemotherapy, before radiation therapy (RT), and 4 weeks into RT and were investigated as an example case. Results: Mean ADC for the tumor drawn on the DWI cases was 0.93, 1.0 and 1.13 10{sup −3}×mm{sup 2}/s before chemotherapy, before RT and 4 weeks into RT. The mean (D.10{sup −3} × mm{sup 2}/s, D* 10{sup −3} × mm{sup 2}/s, and f %) based on biexponential fit was (0.67, 18.6, and 27.2%), (0.72, 17.7, and 28.9%) and (0.83,15.1, and 30.7%) at these time points. The mean (D, D* f) based on segmented fit was (0.72, 10.5, and 12.1%), (0.72, 8.2, and 17.4%) and (.82, 8.1, 16.5%) Conclusion: ADC values are typically higher than true diffusion coefficients. For tumors with significant perfusion effect, ADC should be analyzed at higher b-values or separated from the perfusion component. Biexponential fit overestimates the perfusion fraction because of increased sensitivity to noise at low b-values.« less

Principles of diffusion kurtosis imaging and its role in early diagnosis of neurodegenerative disorders.

PubMed

Arab, Anas; Wojna-Pelczar, Anna; Khairnar, Amit; Szabó, Nikoletta; Ruda-Kucerova, Jana

2018-05-01

Pathology of neurodegenerative diseases can be correlated with intra-neuronal as well as extracellular changes which lead to neuronal degeneration. The central nervous system (CNS) is a complex structure comprising of many biological barriers. These microstructural barriers might be affected by a variety of pathological processes. Specifically, changes in the brain tissue's microstructure affect the diffusion of water which can be assessed non-invasively by diffusion weighted (DW) magnetic resonance imaging (MRI) techniques. Diffusion tensor imaging (DTI) is a diffusion MRI technique that considers diffusivity as a Gaussian process, i.e. does not account for any diffusion hindrance. However, environment of the brain tissues is characterized by a non-Gaussian diffusion. Therefore, diffusion kurtosis imaging (DKI) was developed as an extension of DTI method in order to quantify the non-Gaussian distribution of water diffusion. This technique represents a promising approach for early diagnosis of neurodegenerative diseases when the neurodegenerative process starts. Hence, the purpose of this article is to summarize the ongoing clinical and preclinical research on Parkinson's, Alzheimer's and Huntington diseases, using DKI and to discuss the role of this technique as an early stage biomarker of neurodegenerative conditions. Copyright © 2018 Elsevier Inc. All rights reserved.

ADC histogram analysis for adrenal tumor histogram analysis of apparent diffusion coefficient in differentiating adrenal adenoma from pheochromocytoma.

PubMed

Umanodan, Tomokazu; Fukukura, Yoshihiko; Kumagae, Yuichi; Shindo, Toshikazu; Nakajo, Masatoyo; Takumi, Koji; Nakajo, Masanori; Hakamada, Hiroto; Umanodan, Aya; Yoshiura, Takashi

2017-04-01

To determine the diagnostic performance of apparent diffusion coefficient (ADC) histogram analysis in diffusion-weighted (DW) magnetic resonance imaging (MRI) for differentiating adrenal adenoma from pheochromocytoma. We retrospectively evaluated 52 adrenal tumors (39 adenomas and 13 pheochromocytomas) in 47 patients (21 men, 26 women; mean age, 59.3 years; range, 16-86 years) who underwent DW 3.0T MRI. Histogram parameters of ADC (b-values of 0 and 200 [ADC 200 ], 0 and 400 [ADC 400 ], and 0 and 800 s/mm 2 [ADC 800 ])-mean, variance, coefficient of variation (CV), kurtosis, skewness, and entropy-were compared between adrenal adenomas and pheochromocytomas, using the Mann-Whitney U-test. Receiver operating characteristic (ROC) curves for the histogram parameters were generated to differentiate adrenal adenomas from pheochromocytomas. Sensitivity and specificity were calculated by using a threshold criterion that would maximize the average of sensitivity and specificity. Variance and CV of ADC 800 were significantly higher in pheochromocytomas than in adrenal adenomas (P < 0.001 and P = 0.001, respectively). With all b-value combinations, the entropy of ADC was significantly higher in pheochromocytomas than in adrenal adenomas (all P ≤ 0.001), and showed the highest area under the ROC curve among the ADC histogram parameters for diagnosing adrenal adenomas (ADC 200 , 0.82; ADC 400 , 0.87; and ADC 800 , 0.92), with sensitivity of 84.6% and specificity of 84.6% (cutoff, ≤2.82) with ADC 200 ; sensitivity of 89.7% and specificity of 84.6% (cutoff, ≤2.77) with ADC 400 ; and sensitivity of 94.9% and specificity of 92.3% (cutoff, ≤2.67) with ADC 800 . ADC histogram analysis of DW MRI can help differentiate adrenal adenoma from pheochromocytoma. 3 J. Magn. Reson. Imaging 2017;45:1195-1203. © 2016 International Society for Magnetic Resonance in Medicine.

Spatially constrained incoherent motion method improves diffusion-weighted MRI signal decay analysis in the liver and spleen

PubMed Central

Taimouri, Vahid; Afacan, Onur; Perez-Rossello, Jeannette M.; Callahan, Michael J.; Mulkern, Robert V.; Warfield, Simon K.; Freiman, Moti

2015-01-01

Purpose: To evaluate the effect of the spatially constrained incoherent motion (SCIM) method on improving the precision and robustness of fast and slow diffusion parameter estimates from diffusion-weighted MRI in liver and spleen in comparison to the independent voxel-wise intravoxel incoherent motion (IVIM) model. Methods: We collected diffusion-weighted MRI (DW-MRI) data of 29 subjects (5 healthy subjects and 24 patients with Crohn’s disease in the ileum). We evaluated parameters estimates’ robustness against different combinations of b-values (i.e., 4 b-values and 7 b-values) by comparing the variance of the estimates obtained with the SCIM and the independent voxel-wise IVIM model. We also evaluated the improvement in the precision of parameter estimates by comparing the coefficient of variation (CV) of the SCIM parameter estimates to that of the IVIM. Results: The SCIM method was more robust compared to IVIM (up to 70% in liver and spleen) for different combinations of b-values. Also, the CV values of the parameter estimations using the SCIM method were significantly lower compared to repeated acquisition and signal averaging estimated using IVIM, especially for the fast diffusion parameter in liver (CVIV IM = 46.61 ± 11.22, CVSCIM = 16.85 ± 2.160, p < 0.001) and spleen (CVIV IM = 95.15 ± 19.82, CVSCIM = 52.55 ± 1.91, p < 0.001). Conclusions: The SCIM method characterizes fast and slow diffusion more precisely compared to the independent voxel-wise IVIM model fitting in the liver and spleen. PMID:25832079

Cerebral embolization in asymptomatic versus symptomatic patients after carotid stenting.

PubMed

Tulip, Hans H; Rosero, Eric B; Higuera, Adriana J; Ilarraza, Adriana; Valentine, R James; Timaran, Carlos H

2012-12-01

Previous studies have investigated the development of new ischemic brain lesions on diffusion-weighted magnetic resonance imaging (DW-MRI) after carotid artery stenting (CAS). The rate of ischemic brain injury after CAS for asymptomatic stenosis has not been extensively studied but is presumed to be less likely than in symptomatic patients. This study assessed the occurrence of cerebral embolization after CAS for asymptomatic vs symptomatic carotid stenosis. During an 18-month period, 40 patients undergoing CAS under filter embolic protection were prospectively evaluated. Transcranial Doppler (TCD) during CAS and preprocedural and 24-hour postprocedural DW-MRI were used to assess cerebral embolization. Univariate and nonparametric analyses were used to compare differences in cerebral embolization after CAS in asymptomatic and symptomatic patients. CAS was performed for 23 asymptomatic (58%) and 17 symptomatic (42%) carotid stenoses. The median microembolic counts detected by TCD were 285 (interquartile range [IQR], 182-376) for asymptomatic and 313 (IQR, 170-426) for symptomatic carotid stenosis (P=.6). DW-MRI was available for assessment in 20 asymptomatic and 14 symptomatic patients. New acute cerebral emboli detected with DW-MRI occurred in 10 asymptomatic (50%) and 7 symptomatic patients (50%) undergoing CAS (P=.9). The ipsilateral and total median number of DW-MRI lesions between groups were not statistically significantly different at, respectively, 1 (IQR, 0-2.5) and 1.5 (IQR, 0-3) for asymptomatic vs 0.5 (IQR, 0-2) and 0.5 (IQR, 0-3) for symptomatic carotid stenosis (P>.5). One asymptomatic patient sustained a minor stroke after CAS. No new neurologic events occurred in symptomatic patients. The 30-day stroke-death rate was 2.5% in this series. Cerebral embolization, as detected by TCD and DW-MRI, occurs with a similar frequency after CAS for asymptomatic and symptomatic carotid stenosis. Because postprocedural ischemic brain injury occurs in approximately half of asymptomatic patients, the safety of CAS under filter embolic protection for asymptomatic carotid stenosis is uncertain and warrants further study. Published by Mosby, Inc.

Value of Endorectal MRI in Romanian Men for High Risk of Prostate Cancer: MRI Findings Compared with Saturation Biopsy.

PubMed

Lebovici, A; Sfrangeu, S A; Caraiani, C; Lucan, C; Suciu, M; Elec, F; Iacob, Gh; Buruian, M

2015-01-01

To evaluate the potentials of T2 weighted (T2W)MRI and diffusion weighted (DW) MRI for prostate cancer(PCa) detection, local staging and treatment planning in high-risk group. Endorectal MRI was performed in 17 Romanian men (median age: 66 years; range: 58 75 years), prostate specific antigen (PSA) serum levels (median: 20 ng mL; range: 8.6 100 ng mL) with positive findings for PCa(median Gleason score: 8; range: 7 - 9). Imaging findings were compared to standarised 20-core transperineal saturation biopsy. The prostate was divided into 16 standart sectors(10 posterior and 6 anterior). Overall, prostate cancer was detected in 16 patients(94%) on DW-MRI alone and in all 17 patients (100%) on T2W-MRI alone, and on combined imaging. On T2W-MRI165 sectors out of 272 were suspicious for PCa and 124 (75%)were cancer positive. On DW-MRI 126 sectors out of 272 were suspicious for PCa and 118 (95%) were cancer positive. On the combined imaging approach 134 sectors out of 272 were suspicious for PCa and 126 (94%) were cancer positive. This resulted in diagnostic accuracies per sector of 76% for T2WMRI, 86% for DW-MRI and 89% for combined imaging. Multifocal PCa was confirmed both on MR imaging and by biopsy in 8 of the 17 men (47%) Extra capsular extension(ECE) or seminal vesicles invasion (SVI) was highly suspected in 8 (47%) respectively 7 (41%) of the 17 patients. 6 patients(35%) presented both ECE and SVI. MRI findings were taken into account for treatment planning and none of these patients underwent radical prostatectomy and instead was treated with palliative cryotherapy, radiotherapy and hormone therapy. Endorectal MRI is highly accurate in PCa detection in the high-risk group and seems to have an important role in local staging and treatment planning for Romanian population. Celsius.

Carotid artery stenting with double cerebral embolic protection in asymptomatic patients - a diffusion-weighted MRI controlled study.

PubMed

Vuruskan, Ertan; Saracoglu, Erhan; Ergun, Ugur; Poyraz, Fatih; Duzen, İrfan Veysel

2017-01-01

The aim of this study was to compare the simultaneous double-protection method (proximal balloon plus distal filter) with distal-filter protection or proximal-balloon protection alone in asymptomatic patients during carotid artery stenting. 119 consecutive patients were investigated for carotid artery stentings in the extracranial internal carotid artery with the use of distal filters (n = 41, 34.4 %), proximal balloon (MoMa) protection (n = 40, 33.6 %) or double protection (n = 38, 31.9 %). Magnetic resonance imaging (MRI) was performed on all patients before the procedure, and control diffusion-weighted MRI (DW-MRI) was obtained within 24-48 h after the procedure. Procedural data, complications, success rate, major adverse cardiovascular events, and MRI findings were collected. New cerebral high-intensity (HI) lesions were observed in 47 (39.4 %) patients. HI lesions were observed in 22 (53.6 %), 15 (37.5 %), and 10 (26.3 %) of the patients with distal filters, proximal protection, and double protection, respectively (p = 0.004). The average number of HI lesions on DW-MRI was 1.80 in the distal-filter group, 0.90 in the proximal-balloon group, and 0.55 in the double-protection group (p < 0.001). Procedure and fluoroscopy times were slightly longer in the double-protection group compared to the distal- or proximal-protection groups (p = 0.001). The double (proximal plus distal) cerebral embolic protection technique is safe and effective for minimizing the risk of cerebral embolization, even in patients with asymptomatic carotid artery stenosis, despite slightly longer procedure and fluoroscopy times.
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Detection of soft-tissue sarcoma recurrence: added value of functional MR imaging techniques at 3.0 T.

PubMed

Del Grande, Filippo; Subhawong, Ty; Weber, Kristy; Aro, Michael; Mugera, Charles; Fayad, Laura M

2014-05-01

To determine the added value of functional magnetic resonance (MR) sequences (dynamic contrast material-enhanced [DCE] and quantitative diffusion-weighted [DW] imaging with apparent diffusion coefficient [ADC] mapping) for the detection of recurrent soft-tissue sarcomas following surgical resection. This retrospective study was approved by the institutional review board. The requirement to obtain informed consent was waived. Thirty-seven patients referred for postoperative surveillance after resection of soft-tissue sarcoma (35 with high-grade sarcoma) were studied. Imaging at 3.0 T included conventional (T1-weighted, fluid-sensitive, and contrast-enhanced T1-weighted imaging) and functional (DCE MR imaging, DW imaging with ADC mapping) sequences. Recurrences were confirmed with biopsy or resection. A disease-free state was determined with at least 6 months of follow-up. Two readers independently recorded the signal and morphologic characteristics with conventional sequences, the presence or absence of arterial enhancement at DCE MR imaging, and ADCs of the surgical bed. The accuracy of conventional MR imaging in the detection of recurrence was compared with that with the addition of functional sequences. The Fisher exact and Wilcoxon rank sum tests were used to define the accuracy of imaging features, the Cohen κ and Lin interclass correlation were used to define interobserver variability, and receiver operating characteristic analysis was used to define a threshold to detect recurrence and assess reader confidence after the addition of functional imaging to conventional sequences. There were six histologically proved recurrences in 37 patients. Sensitivity and specificity of MR imaging in the detection of tumor recurrence were 100% (six of six patients) and 52% (16 of 31 patients), respectively, with conventional sequences, 100% (six of six patients) and 97% (30 of 31 patients) with the addition of DCE MR imaging, and 60% (three of five patients) and 97% (30 of 31 patients) with the addition of DW imaging and ADC mapping. The average ADC of recurrence (1.08 mm(2)/sec ± 0.19) was significantly different from those of postoperative scarring (0.9 mm(2)/sec ± 0.00) and hematomas (2.34 mm(2)/sec ± 0.72) (P = .03 for both). The addition of functional MR sequences to a routine MR protocol, in particular DCE MR imaging, offers a specificity of more than 95% for distinguishing recurrent sarcoma from postsurgical scarring.

Over-hydration detection in brain by magnetic induction spectroscopy

NASA Astrophysics Data System (ADS)

González, César A.; Pérez, María; Hevia, Nidiyare; Arámbula, Fernándo; Flores, Omar; Aguilar, Eliot; Hinojosa, Ivonne; Joskowicz, Leo; Rubinsky, Boris

2010-04-01

Detection and continuous monitoring of edema in the brain in early stages is useful for assessment of medical condition and treatment. We have proposed a solution in which the bulk measurements of the tissue electrical properties to detect edema or in general accumulation of fluids are made through measurement of the magnetic induction phase shift between applied and measured currents at different frequencies (Magnetic Induction Spectroscopy; MIS). Magnetic Resonant Imaging (MRI) has been characterized because its capability to detect different levels of brain tissue hydration by differences in diffusion-weighted (DW) sequences and it's involve apparent diffusion coefficient (ADC). The objective of this study was to explore the viability to use measurements of the bulk tissue electrical properties to detect edema or in general accumulation of fluids by MIS. We have induced a transitory and generalized tissue over-hydration condition in ten volunteers ingesting 1.5 to 2 liters of water in ten minutes. Basal and over-hydration conditions were monitored by MIS and MRI. Changes in the inductive phase shift at certain frequencies were consistent with changes in the brain tissue hydration level observed by DW-ADC. The results suggest that MIS has the potential to detect pathologies associated to changes in the content of fluids in brain tissue such as edema and hematomas.

The Spatial Relationship between Apparent Diffusion Coefficient and Standardized Uptake Value of 18F-Fluorodeoxyglucose Has a Crucial Influence on the Numeric Correlation of Both Parameters in PET/MRI of Lung Tumors

PubMed Central

Stieltjes, Bram; Weikert, Thomas; Gatidis, Sergios; Wiese, Mark; Wild, Damian; Lardinois, Didier

2017-01-01

The minimum apparent diffusion coefficient (ADCmin) derived from diffusion-weighted MRI (DW-MRI) and the maximum standardized uptake value (SUVmax) of FDG-PET are markers of aggressiveness in lung cancer. The numeric correlation of the two parameters has been extensively studied, but their spatial interplay is not well understood. After FDG-PET and DW-MRI coregistration, values and location of ADCmin- and SUVmax-voxels were analyzed. The upper limit of the 95% confidence interval for registration accuracy of sequential PET/MRI was 12 mm, and the mean distance (D) between ADCmin- and SUVmax-voxels was 14.0 mm (average of two readers). Spatial mismatch (D > 12 mm) between ADCmin and SUVmax was found in 9/25 patients. A considerable number of mismatch cases (65%) was also seen in a control group that underwent simultaneous PET/MRI. In the entire patient cohort, no statistically significant correlation between SUVmax and ADCmin was seen, while a moderate negative linear relationship (r = −0.5) between SUVmax and ADCmin was observed in tumors with a spatial match (D ≤ 12 mm). In conclusion, spatial mismatch between ADCmin and SUVmax is found in a considerable percentage of patients. The spatial connection of the two parameters SUVmax and ADCmin has a crucial influence on their numeric correlation. PMID:29391862

The distribution of the apparent diffusion coefficient as an indicator of the response to chemotherapeutics in ovarian tumour xenografts

NASA Astrophysics Data System (ADS)

Tourell, Monique C.; Shokoohmand, Ali; Landgraf, Marietta; Holzapfel, Nina P.; Poh, Patrina S. P.; Loessner, Daniela; Momot, Konstantin I.

2017-02-01

Diffusion-weighted magnetic resonance imaging (DW-MRI) was used to evaluate the effects of single-agent and combination treatment regimens in a spheroid-based animal model of ovarian cancer. Ovarian tumour xenografts grown in non-obese diabetic/severe-combined-immunodeficiency (NOD/SCID) mice were treated with carboplatin or paclitaxel, or combination carboplatin/paclitaxel chemotherapy regimens. After 4 weeks of treatment, tumours were extracted and underwent DW-MRI, mechanical testing, immunohistochemical and gene expression analyses. The distribution of the apparent diffusion coefficient (ADC) exhibited an upward shift as a result of each treatment regimen. The 99-th percentile of the ADC distribution (“maximum ADC”) exhibited a strong correlation with the tumour size (r2 = 0.90) and with the inverse of the elastic modulus (r2 = 0.96). Single-agent paclitaxel (n = 5) and combination carboplatin/paclitaxel (n = 2) treatment regimens were more effective in inducing changes in regions of higher cell density than single-agent carboplatin (n = 3) or the no-treatment control (n = 5). The maximum ADC was a good indicator of treatment-induced cell death and changes in the extracellular matrix (ECM). Comparative analysis of the tumours’ ADC distribution, mechanical properties and ECM constituents provides insights into the molecular and cellular response of the ovarian tumour xenografts to chemotherapy. Increased sample sizes are recommended for future studies. We propose experimental approaches to evaluation of the timeline of the tumour’s response to treatment.

The Spatial Relationship between Apparent Diffusion Coefficient and Standardized Uptake Value of 18F-Fluorodeoxyglucose Has a Crucial Influence on the Numeric Correlation of Both Parameters in PET/MRI of Lung Tumors.

PubMed

Sauter, Alexander W; Stieltjes, Bram; Weikert, Thomas; Gatidis, Sergios; Wiese, Mark; Klarhöfer, Markus; Wild, Damian; Lardinois, Didier; Bremerich, Jens; Sommer, Gregor

2017-01-01

The minimum apparent diffusion coefficient (ADC min ) derived from diffusion-weighted MRI (DW-MRI) and the maximum standardized uptake value (SUV max ) of FDG-PET are markers of aggressiveness in lung cancer. The numeric correlation of the two parameters has been extensively studied, but their spatial interplay is not well understood. After FDG-PET and DW-MRI coregistration, values and location of ADC min - and SUV max -voxels were analyzed. The upper limit of the 95% confidence interval for registration accuracy of sequential PET/MRI was 12 mm, and the mean distance ( D ) between ADC min - and SUV max -voxels was 14.0 mm (average of two readers). Spatial mismatch ( D > 12 mm) between ADC min and SUV max was found in 9/25 patients. A considerable number of mismatch cases (65%) was also seen in a control group that underwent simultaneous PET/MRI. In the entire patient cohort, no statistically significant correlation between SUV max and ADC min was seen, while a moderate negative linear relationship ( r = -0.5) between SUV max and ADC min was observed in tumors with a spatial match ( D ≤ 12 mm). In conclusion, spatial mismatch between ADC min and SUV max is found in a considerable percentage of patients. The spatial connection of the two parameters SUV max and ADC min has a crucial influence on their numeric correlation.

Density Weighted FDF Equations for Simulations of Turbulent Reacting Flows

NASA Technical Reports Server (NTRS)

Shih, Tsan-Hsing; Liu, Nan-Suey

2011-01-01

In this report, we briefly revisit the formulation of density weighted filtered density function (DW-FDF) for large eddy simulation (LES) of turbulent reacting flows, which was proposed by Jaberi et al. (Jaberi, F.A., Colucci, P.J., James, S., Givi, P. and Pope, S.B., Filtered mass density function for Large-eddy simulation of turbulent reacting flows, J. Fluid Mech., vol. 401, pp. 85-121, 1999). At first, we proceed the traditional derivation of the DW-FDF equations by using the fine grained probability density function (FG-PDF), then we explore another way of constructing the DW-FDF equations by starting directly from the compressible Navier-Stokes equations. We observe that the terms which are unclosed in the traditional DW-FDF equations are now closed in the newly constructed DW-FDF equations. This significant difference and its practical impact on the computational simulations may deserve further studies.

Early effects of low dose bevacizumab treatment assessed by magnetic resonance imaging.

PubMed

Gaustad, Jon-Vidar; Simonsen, Trude G; Smistad, Ragnhild; Wegner, Catherine S; Andersen, Lise Mari K; Rofstad, Einar K

2015-11-14

Antiangiogenic treatments have been shown to increase blood perfusion and oxygenation in some experimental tumors, and to reduce blood perfusion and induce hypoxia in others. The purpose of this preclinical study was to investigate the potential of dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) and diffusion weighted MRI (DW-MRI) in assessing early effects of low dose bevacizumab treatment, and to investigate intratumor heterogeneity in this effect. A-07 and R-18 human melanoma xenografts, showing high and low expression of VEGF-A, respectively, were used as tumor models. Untreated and bevacizumab-treated tumors were subjected to DCE-MRI and DW-MRI before treatment, and twice during a 7-days treatment period. Tumor images of Ktrans (the volume transfer constant of Gd-DOTA) and ve (the fractional distribution volume of Gd-DOTA) were produced by pharmacokinetic analysis of the DCE-MRI data, and tumor images of ADC (the apparent diffusion coefficient) were produced from DW-MRI data. Untreated A-07 tumors showed higher Ktrans, v e, and ADC values than untreated R-18 tumors. Untreated tumors showed radial heterogeneity in Ktrans, i.e., Ktrans was low in central tumor regions and increased gradually towards the tumor periphery. After the treatment, bevacizumab-treated A-07 tumors showed lower Ktrans values than untreated A-07 tumors. Peripherial tumor regions showed substantial reductions in Ktrans, whereas little or no effect was seen in central regions. Consequently, the treatment altered the radial heterogeneity in Ktrans. In R-18 tumors, significant changes in Ktrans were not observed. Treatment induced changes in tumor size, v e, and ADC were not seen in any of the tumor lines. Early effects of low dose bevacizumab treatment may be highly heterogeneous within tumors and can be detected with DCE-MRI.

The Role of Diffusion-Weighted Magnetic Resonance Imaging in the Treatment Response Evaluation of Hepatocellular Carcinoma Patients Treated With Radiation Therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu, Jeong Il; Park, Hee Chul, E-mail: hee.ro.park@skku.edu; Lim, Do Hoon

2014-07-15

Purpose: We investigated the role of diffusion-weighted magnetic resonance imaging (DW MRI) as a response evaluation indicator for hepatocellular carcinoma (HCC) treated with radiation therapy (RT). Methods and Materials: Inclusion criteria of this retrospective study were DW MRI acquisition within 1 month before and 3 to 5 months after RT. In total, 48 patients were enrolled. Two radiation oncologists measured the apparent diffusion coefficient (ADC). Possible predictive factors, including alteration of the ADC value before and 3 to 5 month after RT, in relation to local progression-free survival (LPFS) were analyzed and compared. Results: Three months after RT, 6 patients (12.5%) showed amore » complete response, and 27 patients (56.3%) showed a partial response when evaluated using the modified response evaluation criteria in solid tumors (mRECIST). The average ADC ± SD values were 1.21 ± 0.27 ( × 10{sup −3} mm{sup 2}/s) before and 1.41 ± 0.36 ( × 10{sup −3} mm{sup 2}/s) after RT (P<.001). The most significant prognostic factor related to LPFS was mRECIST (P<.001). The increment of ADC value (≥20%) was also a significant factor (P=.02), but RECIST (version 1.1; P=.11) was not. When RECIST was combined with the increment of ADC value (≥20%), the LPFS rates were significantly different between the groups (P=.004), and the area under the curve value (0.745) was comparable with that of mRECIST (0.765). Conclusions: ADC value change before and after RT in HCC was closely related to LPFS. ADC value and RECIST may substitute for mRECIST in patients who cannot receive contrast agents.« less

Acute pyelonephritis in transplanted kidneys: can diffusion-weighted magnetic resonance imaging be useful for diagnosis and follow-up?

PubMed

Faletti, Riccardo; Cassinis, Maria Carla; Gatti, Marco; Giglio, Jacopo; Guarnaccia, Carla; Messina, Marina; Bergamasco, Laura; Fonio, Paolo

2016-03-01

To assess reliability of diffusion-weighted magnetic resonance imaging (DW-MRI) in the management of acute pyelonephritis (APN) foci in transplanted kidneys. In the 2012-2014 period, 24 kidney-transplanted patients underwent MR screening for clinical suspicion of APN. Two readers independently analyzed all images, establishing presence and location of APN foci. The 22 patients who were positive at the MR exam constituted the study population. For each patient the apparent diffusion coefficient (ADC) was measured in the APN foci and in three sites of the healthy parenchyma (case-control comparison). The data were matched to the laboratory measurements for white blood cell, C-reactive protein, and serum creatinine. Forty-six APN foci were found in 22/24 patients. At the acute stage, the difference in ADC between healthy parenchyma and APN foci was significant (2.06 ± 0.16 vs. 1.43 ± 0.32 × 10(-3) mm(2)/s; p < 0.0001). The performance of ADC as APN indicator was tested by the receiving operating characteristics (ROC) curve: the area under curve AUC = 0.99 witnessed an excellent discriminatory ability, with threshold APN/normal parenchyma 1.9 × 10(-3) mm(2)/s. At the 1-month follow-up 43/46 APN foci were no longer visible, with ADC values significantly higher than at the acute stage; all laboratory data were physiological, with WBC significantly reduced from the acute phase (5.2 ± 1.6 × 10(9)/L vs. 10.6 ± 4.8 × 10(9)/L; p < 0.0001). The other 3 patients underwent further therapy and exams, including a third MR. DW-MRI with ADC measurement seems to be a reliable tool in diagnosing and monitoring APN foci in transplanted kidneys, with clinical impact on patient management.

Modulation of renal oxygenation and perfusion in rat kidney monitored by quantitative diffusion and blood oxygen level dependent magnetic resonance imaging on a clinical 1.5T platform.

PubMed

Jerome, Neil P; Boult, Jessica K R; Orton, Matthew R; d'Arcy, James; Collins, David J; Leach, Martin O; Koh, Dow-Mu; Robinson, Simon P

2016-10-03

To investigate the combined use of intravoxel incoherent motion (IVIM) diffusion-weighted (DW) and blood oxygen level dependent (BOLD) magnetic resonance imaging (MRI) to assess rat renal function using a 1.5T clinical platform. Multiple b-value DW and BOLD MR images were acquired from adult rats using a parallel clinical coil arrangement, enabling quantitation of the apparent diffusion coefficient (ADC), IVIM-derived diffusion coefficient (D), pseudodiffusion coefficient (D*) and perfusion fraction (f), and the transverse relaxation time T 2 *, for whole kidney, renal cortex, and medulla. Following the acquisition of two baseline datasets to assess measurement repeatability, images were acquired following i.v. administration of hydralazine, furosemide, or angiotensin II for up to 40 min. Excellent repeatability (CoV <10 %) was observed for ADC, D, f and T 2 * measured over the whole kidney. Hydralazine induced a marked and significant (p < 0.05) reduction in whole kidney ADC, D, and T 2 *, and a significant (p < 0.05) increase in D* and f. Furosemide significantly (p < 0.05) increased whole kidney ADC, D, and T 2 *. A more variable response to angiotensin II was determined, with a significant (p < 0.05) increase in medulla D* and significant (p < 0.05) reduction in whole kidney T 2 * established. Multiparametric MRI, incorporating quantitation of IVIM DWI and BOLD biomarkers and performed on a clinical platform, can be used to monitor the acute effects of vascular and tubular modulating drugs on rat kidney function in vivo. Clinical adoption of such functional imaging biomarkers can potentially inform on treatment effects in patients with renal dysfunction.

The Potential for an Enhanced Role for MRI in Radiation-therapy Treatment Planning

PubMed Central

Metcalfe, P.; Liney, G. P.; Holloway, L.; Walker, A.; Barton, M.; Delaney, G. P.; Vinod, S.; Tomé, W.

2013-01-01

The exquisite soft-tissue contrast of magnetic resonance imaging (MRI) has meant that the technique is having an increasing role in contouring the gross tumor volume (GTV) and organs at risk (OAR) in radiation therapy treatment planning systems (TPS). MRI-planning scans from diagnostic MRI scanners are currently incorporated into the planning process by being registered to CT data. The soft-tissue data from the MRI provides target outline guidance and the CT provides a solid geometric and electron density map for accurate dose calculation on the TPS computer. There is increasing interest in MRI machine placement in radiotherapy clinics as an adjunct to CT simulators. Most vendors now offer 70 cm bores with flat couch inserts and specialised RF coil designs. We would refer to these devices as MR-simulators. There is also research into the future application of MR-simulators independent of CT and as in-room image-guidance devices. It is within the background of this increased interest in the utility of MRI in radiotherapy treatment planning that this paper is couched. The paper outlines publications that deal with standard MRI sequences used in current clinical practice. It then discusses the potential for using processed functional diffusion maps (fDM) derived from diffusion weighted image sequences in tracking tumor activity and tumor recurrence. Next, this paper reviews publications that describe the use of MRI in patient-management applications that may, in turn, be relevant to radiotherapy treatment planning. The review briefly discusses the concepts behind functional techniques such as dynamic contrast enhanced (DCE), diffusion-weighted (DW) MRI sequences and magnetic resonance spectroscopic imaging (MRSI). Significant applications of MR are discussed in terms of the following treatment sites: brain, head and neck, breast, lung, prostate and cervix. While not yet routine, the use of apparent diffusion coefficient (ADC) map analysis indicates an exciting future application for functional MRI. Although DW-MRI has not yet been routinely used in boost adaptive techniques, it is being assessed in cohort studies for sub-volume boosting in prostate tumors. PMID:23617289

Gold concentrations in abiotic materials, plants, and animals: a synoptic review

USGS Publications Warehouse

Eisler, R.

2004-01-01

Gold (Au) is ubiquitous in the environment and mined commercially at numerous locations worldwide. It is also an allergen that induces dermatitis in sensitive individuals. Gold concentrations were comparatively elevated in samples collected near gold mining and processing facilities, although no data were found for birds and non-human mammals. Maximum gold concentrations reported in abiotic materials were 0.001 ug/L in rainwater; 0.0015 ug/L in seawater near hydrothermal vents vs. <0.00004-0.0007 ug/L elsewhere; 5.0 ug/kg dry weight (DW) in the Earth's crust; 19.0 ug/L in a freshwater stream near a gold mining site; 440 ug/kg DW in atmospheric dust near a high traffic road; 843 ug/kg DW in alluvial soil near a Nevada gold mine vs. <29 ug/kg DW premining; 2.53 mg/kg DW in snow near a Russian smelter vs. <0.35 mg/kg DW at a reference site; 4.5 mg/kg DW in sewage sludge; 28.7 mg/kg DW in polymetallic sulfides from the ocean floor; and 256.0 mg/kg DW in freshwater sediments near a gold mine tailings pile vs. <5 ug/kg DW prior to mining. In plants, elevated concentrations of 19 ug Au/kg DW were reported in terrestrial vegetation near gold mining operations vs. <4 ug/kg DW at a reference site; 37 ug/kg DW in aquatic bryophytes downstream from a gold mine; 150 ug Au/kg DW in leaves of beans grown in soil containing 170 ug/kg DW; up to 1.06 mg/kg DW in algal mats of rivers receiving gold mine wastes; and 0.1-100 mg/kg DW in selected gold accumulator plants. Fish and aquatic invertebrates contained 0.1-38.0 ug Au/kg DW. In humans, gold concentrations up to 1.1 ug/L were documented in urine of dental technicians vs. 0.002-0.85 ug/L in reference populations; 2.1 ug/L in breast milk, attributed to gold dental fillings and jewelry of mothers; 1.4 mg/kg DW in hair of goldsmiths vs. a normal range of 6-880 ug/kg DW; 2.39 mg/L in whole blood of rheumatoid arthritis patients receiving gold thiol drugs to reduce inflammation (chrysotherapy) vs. a normal range of 0.2-2.0 ug/L; and 60.0 to 233.0 mg/kg fresh weight (FW) in kidneys of rheumatoid arthritis patients undergoing active chrysotherapy vs. <42.0 mg/kg FW kidney 140 months posttreatment.

Evaluation of Alzheimer's disease by analysis of MR images using Objective Dialectical Classifiers as an alternative to ADC maps.

PubMed

Dos Santos, Wellington P; de Assis, Francisco M; de Souza, Ricardo E; Dos Santos Filho, Plinio B

2008-01-01

Alzheimer's disease is the most common cause of dementia, yet hard to diagnose precisely without invasive techniques, particularly at the onset of the disease. This work approaches image analysis and classification of synthetic multispectral images composed by diffusion-weighted (DW) magnetic resonance (MR) cerebral images for the evaluation of cerebrospinal fluid area and measuring the advance of Alzheimer's disease. A clinical 1.5 T MR imaging system was used to acquire all images presented. The classification methods are based on Objective Dialectical Classifiers, a new method based on Dialectics as defined in the Philosophy of Praxis. A 2-degree polynomial network with supervised training is used to generate the ground truth image. The classification results are used to improve the usual analysis of the apparent diffusion coefficient map.

Spatial distribution of and seasonal variations in endosulfan concentrations in soil, air, and biota around a contaminated site.

PubMed

Fang, Yanyan; Nie, Zhiqiang; Yang, Jinzhong; Die, Qingqi; Tian, Yajun; Liu, Feng; He, Jie; Wang, Jianyuan; Huang, Qifei

2018-06-12

Soil, air, tree bark, rice, wheat, invertebrates, and chicken tissues around a typical endosulfan-contaminated site were analyzed in each season in each of two years. The total endosulfan (the sum of α-, β-endosulfan and endosulfan sulfate) were significantly different in soil and air samples collected in the four seasons (P < 0.01) and the mean concentrations were 6.53 ng/g dry weight (d.w.) and 2.40 ng/m 3 , respectively, in autumn, 3.32 ng/g d.w. and 2.48 ng/m 3 , respectively, in winter, 2.10 ng/g d.w. and 0.93 ng/m 3 , respectively, in spring, and 1.03 ng/g d.w. and 0.83 ng/m 3 , respectively, in summer. The total endosulfan concentrations in tree bark, rice, wheat, and invertebrates were 23.0-278 (mean 95.5) ng/g d.w., 7.36-35.5 (mean 17.4) ng/g d.w., 34.3-158 (mean 83.1) ng/g d.w., and 401-4354 (mean 2125) ng/g lipid weight, respectively. The total endosulfan concentrations in the chicken gizzard, heart, liver, and meat samples were 552, 212, 699, and 221 ng/g lipid weight, respectively. The endosulfan concentrations in soil, air, and biota around the site were strongly influenced by endosulfan emissions from the site, and the concentrations had decreased to half the initial concentrations six months after endosulfan production stopped. The invertebrate and chicken bioconcentration and biomagnification factors indicated that endosulfan accumulated in the invertebrates and chicken tissues was slightly biomagnified by chickens. Copyright © 2018 Elsevier Inc. All rights reserved.

Incorporating drug delivery into an imaging-driven, mechanics-coupled reaction diffusion model for predicting the response of breast cancer to neoadjuvant chemotherapy: theory and preliminary clinical results

NASA Astrophysics Data System (ADS)

Jarrett, Angela M.; Hormuth, David A.; Barnes, Stephanie L.; Feng, Xinzeng; Huang, Wei; Yankeelov, Thomas E.

2018-05-01

Clinical methods for assessing tumor response to therapy are largely rudimentary, monitoring only temporal changes in tumor size. Our goal is to predict the response of breast tumors to therapy using a mathematical model that utilizes magnetic resonance imaging (MRI) data obtained non-invasively from individual patients. We extended a previously established, mechanically coupled, reaction-diffusion model for predicting tumor response initialized with patient-specific diffusion weighted MRI (DW-MRI) data by including the effects of chemotherapy drug delivery, which is estimated using dynamic contrast-enhanced (DCE-) MRI data. The extended, drug incorporated, model is initialized using patient-specific DW-MRI and DCE-MRI data. Data sets from five breast cancer patients were used—obtained before, after one cycle, and at mid-point of neoadjuvant chemotherapy. The DCE-MRI data was used to estimate spatiotemporal variations in tumor perfusion with the extended Kety–Tofts model. The physiological parameters derived from DCE-MRI were used to model changes in delivery of therapy drugs within the tumor for incorporation in the extended model. We simulated the original model and the extended model in both 2D and 3D and compare the results for this five-patient cohort. Preliminary results show reductions in the error of model predicted tumor cellularity and size compared to the experimentally-measured results for the third MRI scan when therapy was incorporated. Comparing the two models for agreement between the predicted total cellularity and the calculated total cellularity (from the DW-MRI data) reveals an increased concordance correlation coefficient from 0.81 to 0.98 for the 2D analysis and 0.85 to 0.99 for the 3D analysis (p  <  0.01 for each) when the extended model was used in place of the original model. This study demonstrates the plausibility of using DCE-MRI data as a means to estimate drug delivery on a patient-specific basis in predictive models and represents a step toward the goal of achieving individualized prediction of tumor response to therapy.

Determination of mouse skeletal muscle architecture using three-dimensional diffusion tensor imaging.

PubMed

Heemskerk, Anneriet M; Strijkers, Gustav J; Vilanova, Anna; Drost, Maarten R; Nicolay, Klaas

2005-06-01

Muscle architecture is the main determinant of the mechanical behavior of skeletal muscles. This study explored the feasibility of diffusion tensor imaging (DTI) and fiber tracking to noninvasively determine the in vivo three-dimensional (3D) architecture of skeletal muscle in mouse hind leg. In six mice, the hindlimb was imaged with a diffusion-weighted (DW) 3D fast spin-echo (FSE) sequence followed by the acquisition of an exercise-induced, T(2)-enhanced data set. The data showed the expected fiber organization, from which the physiological cross-sectional area (PCSA), fiber length, and pennation angle for the tibialis anterior (TA) were obtained. The values of these parameters ranged from 5.4-9.1 mm(2), 5.8-7.8 mm, and 21-24 degrees , respectively, which is in agreement with values obtained previously with the use of invasive methods. This study shows that 3D DT acquisition and fiber tracking is feasible for the skeletal muscle of mice, and thus enables the quantitative determination of muscle architecture.

Increase in Dry Weight and Total Nitrogen Content in Zea mays and Setaria italica Associated with Nitrogen-fixing Azospirillum spp. 1

PubMed Central

Cohen, Efraim; Okon, Yaacov; Kigel, Jaime; Nur, Israel; Henis, Yigal

1980-01-01

The association between nitrogen-fixing bacteria from the genus Azospirillum and the grasses Zea mays and Setaria italica was investigated in sterilized Leonard-jar assemblies. Nitrogen-fixing bacteria isolated from Cynodon dactylon roots in Israel and Azospirillum brasilense (Sp-7, Sp-80, and Cd) were examined. C2H2 reduction activity was detected in systems containing 0.0 to 0.08 but not in those containing 0.16 gram per liter NH4NO3. The organisms tested significantly increased plant dry weight (50-100%), total N content of leaves (50-100%) and C2H4 production (300-1000 nanomoles C2H4 per plant per hour). Highest C2H2 reduction activities were obtained above 30 C and with high light intensities. Significant increases in S. italica dry weight (DW) and nitrogen (N) content were observed in sand (DW = 80%, N = 150%), sandy loam soil (DW = 80%, N = 75%) and loess (DW = 37%, N = 25%). The results obtained in this work clearly demonstrate the potential benefit of inoculating grasses with Azospirillum. PMID:16661514

Gold concentrations in abiotic materials, plants, and animals: a synoptic review.

PubMed

Eisler, R

2004-01-01

Gold (Au) is ubiquitous in the environment and mined commercially at numerous locations worldwide. It is also an allergen that induces dermatitis in sensitive individuals. Gold concentrations were comparatively elevated in samples collected near gold mining and processing facilities, although no data were found for birds and non-human mammals. Maximum gold concentrations reported in abiotic materials were 0.001 microg L(-1) in rainwater; 0.0015 microg L(-1) in seawater near hydrothermal vents vs. < 0.00004-0.0007 microg L(-1) elsewhere; 5.0 microg kg(-1) dry weight (DW) in the Earth's crust; 19.0 microg L(-1) in a freshwater stream near a gold mining site; 440 microg kg(-1) DW in atmospheric dust near a high traffic road; 843 microg kg(-1) DW in alluvial soil near a Nevada gold mine vs. < 29 microg kg(-1) DW premining; 2.53 mg kg(-1) DW in snow near a Russian smelter vs. < 0.35 mg kg(-1) DW at a reference site; 4.5 mg kg(-1) DW in sewage sludge; 28.7 mg kg(-1) DW in polymetallic sulfides from the ocean floor; and 256.0 mg kg(-1) DW in freshwater sediments near a gold mine tailings pile vs. < 5 microg kg(-1) DW prior to mining. In plants, elevated concentrations of 19 microg Au kg(-1) DW were reported in terrestrial vegetation near gold mining operations vs. < 4 microg kg(-1) DW at a reference site; 37 microg kg(-1) DW in aquatic bryophytes downstream from a gold mine; 150 microg Au kg(-1) DW in leaves of beans grown in soil containing 170 microg kg(-1) DW; up to 1.06 mg kg(-1) DW in algal mats of rivers receiving gold mine wastes; and 0.1-100 mg kg(-1) DW in selected gold accumulator plants. Fish and aquatic invertebrates contained 0.1-38.0 microg Au kg(-1) DW. In humans, gold concentrations up to 1.1 microg L(-1) were documented in urine of dental technicians vs. 0.002-0.85 microg L(-1) in reference populations; 2.1 microg L(-1) in breast milk, attributed to gold dental fillings and jewelry of mothers; 1.4 mg kg(-1) DW in hair of goldsmiths vs. a normal range of 6-880 microg kg(-1) DW; 2.39 mg L(-1) in whole blood of rheumatoid arthritis patients receiving gold thiol drugs to reduce inflammation (chrysotherapy) vs. a normal range of 0.2-2.0 microg L(-1); and 60.0 to 233.0 mg kg(-1) fresh weight (FW) in kidneys of rheumatoid arthritis patients undergoing active chrysotherapy vs. < 42.0 mg kg(-1) FW kidney 140 months posttreatment.

Functional and structural correlates of magnetic resonance patterns in a new in vitro model of cerebral ischemia by transient occlusion of the medial cerebral artery.

PubMed

Breschi, Gian Luca; Librizzi, Laura; Pastori, Chiara; Zucca, Ileana; Mastropietro, Alfonso; Cattalini, Alessandro; de Curtis, Marco

2010-08-01

Magnetic resonance imaging (MRI) during the acute phase of a stroke contributes to recognize ischemic regions and is potentially useful to predict clinical outcome. Yet, the functional significance of early MRI alterations during brain ischemia is not clearly understood. We achieved an experimental study to interpret MRI signals in a novel model of focal ischemia in the in vitro isolated guinea pig brain. By combining neurophysiological and morphological analysis with MR-imaging, we evaluated the suitability of MR to identify ischemic and peri-ischemic regions. Extracellular recordings demonstrated depolarizations in the ischemic core, but not in adjacent areas, where evoked activity was preserved and brief peri-infarct depolarizations occurred. Diffusion-weighted MRI and immunostaining performed after neurophysiological characterization showed changes restricted to the core region. Diffusion-weighted MR alterations did not include the penumbra region characterized by peri-infarct depolarizations. Therefore, by comparing neurophysiological, imaging and anatomical data, we can conclude that DW-MRI underestimates the extension of the tissue damage involved in brain ischemia.

Diffusion-weighted magnetic resonance imaging in the characterization of testicular germ cell neoplasms: Effect of ROI methods on apparent diffusion coefficient values and interobserver variability.

PubMed

Tsili, Athina C; Ntorkou, Alexandra; Astrakas, Loukas; Xydis, Vasilis; Tsampalas, Stavros; Sofikitis, Nikolaos; Argyropoulou, Maria I

2017-04-01

To evaluate the difference in apparent diffusion coefficient (ADC) measurements at diffusion-weighted (DW) magnetic resonance imaging of differently shaped regions-of-interest (ROIs) in testicular germ cell neoplasms (TGCNS), the diagnostic ability of differently shaped ROIs in differentiating seminomas from nonseminomatous germ cell neoplasms (NSGCNs) and the interobserver variability. Thirty-three TGCNs were retrospectively evaluated. Patients underwent MR examinations, including DWI on a 1.5-T MR system. Two observers measured mean tumor ADCs using four distinct ROI methods: round, square, freehand and multiple small, round ROIs. The interclass correlation coefficient was analyzed to assess interobserver variability. Statistical analysis was used to compare mean ADC measurements among observers, methods and histologic types. All ROI methods showed excellent interobserver agreement, with excellent correlation (P<0.001). Multiple, small ROIs provided the lower mean ADC in TGCNs. Seminomas had lower mean ADC compared to NSGCNs for each ROI method (P<0.001). Round ROI proved the most accurate method in characterizing TGCNS. Interobserver variability in ADC measurement is excellent, irrespective of the ROI shape. Multiple, small round ROIs and round ROI proved the more accurate methods for ADC measurement in the characterization of TGCNs and in the differentiation between seminomas and NSGCNs, respectively. Copyright © 2017 Elsevier B.V. All rights reserved.

Proximal balloon occlusion versus distal filter protection in carotid artery stenting: A meta-analysis and review of the literature.

PubMed

Omran, Jad; Mahmud, Ehtisham; White, Christopher J; Aronow, Herbert D; Drachman, Douglas E; Gray, William; Abdullah, Obai; Abu-Fadel, Mazen; Firwana, Belal; Mishkel, Gergory; Al-Dadah, Ashraf S

2017-04-01

Carotid artery stenting (CAS) is typically performed using embolic protection devices (EPDs) as a means to reduce the risk of procedure-related stroke. In this study, we compared procedural morbidity and mortality associated with distal (D-EPD) vs. proximal (P-EPD) protection. MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials were queried from January 1998 through May 2015. Only studies comparing (D-EPD) and (P-EPD) were included. Two independent reviewers selected and appraised studies and extracted data in duplicate. Random-effects meta-analysis was used to pool outcomes across studies. Heterogeneity of treatment effect among studies was assessed using the I 2 statistics. Publication bias was assessed using inspection of funnel plots. The primary endpoints included 30-day mortality and stroke. Secondary endpoints included new cerebral lesions on diffusion-weighted magnetic resonance imaging (DW-MRI) and contralateral lesions on DW-MRI. A total of 12,281 patients were included from 18 studies (13 prospective and 5 retrospective) comparing (D-EPD) and (P-EPD) in the setting of CAS. The mean patient age was 69 years and 64% of patients were male. No evidence of publication bias was detected. There was no significant difference between the two modalities in terms of the risk of stroke (risk difference [RD] 0.0, 95% confidence interval [CI] -0.01 to 0.01) or mortality (RD 0.0, 95% CI -0.01 to 0.01) nor was there any difference in the incidence of new cerebral lesions on DW-MRI or contralateral DW-MRI lesions. In patients undergoing CAS, both D-EPD and P-EPD provide similar levels of protection from peri-procedural stroke and 30 days mortality. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Biorecovery of gold

USGS Publications Warehouse

Eisler, R.

2003-01-01

Recovery of ionic and metallic gold (Au) from a wide variety of solutions by selected species of bacteria, yeasts, fungi, algae, and higher plants is documented. Gold accumulations were up to 7.0 g/kg dry weight (DW) in various species of bacteria, 25.0 g/kg DW in freshwater algae, 84.0 g/kg DW in peat, and 100.0 g/kg DW in dried fungus mixed with keratinous material. Mechanisms of accumulation include oxidation, dissolution, reduction, leaching, and sorption. Uptake patterns are significantly modified by the physicochemical milieu. Crab exoskeletons accumulate up to 4.9 g Au/kg DW; however, gold accumulations in various tissues of living teleosts, decapod crustaceans, and bivalve molluscs are negligible.

Variation of growth in height and weight of children. II. After infancy.

PubMed

Sorva, R; Lankinen, S; Tolppanen, E M; Perheentupa, J

1990-05-01

To provide for early detection of abnormal changes in growth, we propose the monitoring of all children for changes in relative height and relative weight as indirect indicators of growth velocity. To this end we analyzed the growth of 2,156 children, as recorded by the child health surveillance services at ages 2 to 19 years. From their data we constructed growth standards on charts of a novel type, which allow direct reading of relative height (SD score, SDS) and relative weight (percentage deviation of weight from median weight for height and sex, %DW). Variation in height explained most (mean 60%) of the variation in weight, and age did not contribute significantly. Hence, our weight charts are height-based. Next, we defined the variations of changes in (delta) SDS and %DW during the different periods of growth. The group means of changes in each period were zero. Variation in delta SDS is widest at the earliest ages, then decreases until year 9-10 (girls) and 10-11 (boys), and again increases. For delta %DW the picture is similar. We present these variations as diagrams for use in growth screening.

Adiposity profile in the dwarf rat: an unusually lean model of profound growth hormone deficiency.

PubMed

Davies, Jeffrey S; Gevers, Evelien F; Stevenson, Amy E; Coschigano, Karen T; El-Kasti, Muna M; Bull, Melanie J; Elford, Carole; Evans, Bronwen A J; Kopchick, John J; Wells, Timothy

2007-05-01

This study describes the previously uncharacterized ontogeny and regulation of truncal adipose reserves in the profoundly GH-deficient dwarf (dw/dw) rat. We show that, despite normal proportionate food intake, dw/dw rats develop abdominal leanness and hypoleptinemia (circulating leptin halved in dw/dw males, P < 0.05) during puberty. This contrasts with the hyperleptinemia seen in moderately GH-deficient Tgr rats (circulating leptin doubled at 6 wk of age, P < 0.05) and in GH receptor-binding protein (GHR/BP)-null mice (circulating leptin doubled; P < 0.05). This lean/hypoleptinemic phenotype was not completely normalized by GH treatment, but dw/dw rats developed abdominal obesity in response to neonatal MSG treatment or maintenance on a high-fat diet. Unlike Tgr rats, dw/dw rats did not become obese with age; plasma leptin levels and fat pad weights became similar to those in wild-type rats. In contrast with truncal leanness, tibial marrow adiposity was normal in male and doubled in female dwarves (P < 0.01), this increase being attributable to increased adipocyte number (P < 0.01). Neonatal MSG treatment and high-fat feeding elevated marrow adiposity in dw/dw rats by inducing adipocyte enlargement (P < 0.05). These results demonstrate that, despite lipolytic influence of GH, severe GH deficiency in dw/dw rats is accompanied by a paradoxical leanness. This lean/hypoleptinemic phenotype is not solely attributable to reduced GH signaling and does not appear to result from a reduction in nutrient intake or the ability of dw/dw adipocytes to accumulate lipid. Disruption of preadipocyte differentiation or adipocyte proliferation in the dw/dw rat may lead to the development of this unusually lean/hypoleptinemic phenotype.

Evidence of sharp and diffuse domain walls in BiFeO3 by means of unit-cell-wise strain and polarization maps obtained with high resolution scanning transmission electron microscopy.

PubMed

Lubk, A; Rossell, M D; Seidel, J; He, Q; Yang, S Y; Chu, Y H; Ramesh, R; Hÿtch, M J; Snoeck, E

2012-07-27

Domain walls (DWs) substantially influence a large number of applications involving ferroelectric materials due to their limited mobility when shifted during polarization switching. The discovery of greatly enhanced conduction at BiFeO(3) DWs has highlighted yet another role of DWs as a local material state with unique properties. However, the lack of precise information on the local atomic structure is still hampering microscopical understanding of DW properties. Here, we examine the atomic structure of BiFeO(3) 109° DWs with pm precision by a combination of high-angle annular dark-field scanning transmission electron microscopy and a dedicated structural analysis. By measuring simultaneously local polarization and strain, we provide direct experimental proof for the straight DW structure predicted by ab initio calculations as well as the recently proposed theory of diffuse DWs, thus resolving a long-standing discrepancy between experimentally measured and theoretically predicted DW mobilities.

Clinicoradiological Correlation of Infarct Patterns on Diffusion-weighted Magnetic Resonance Imaging in Stroke.

PubMed

Hussain, Zainab; Hilal, Kiran; Ahmad, Muhammad; Sajjad, Zafar; Sayani, Raza

2018-03-02

Diffusion-weighted magnetic resonance imaging (DW-MRI) represents a major advance in the early diagnosis of acute ischemic stroke. It can detect edema due to ischemia in the brain tissue. It not only establishes the presence and location of ischemic brain injury but also a relatively new concept is the determination of infarct patterns seen on diffusion imaging and its clinical correlation. Objective To determine the frequency of various infarct patterns and their relationship with functional outcome of the patient. Materials and methods A total of 108 patients with acute stroke were enrolled by purposive sampling. Magnetic resonance imaging (MRI) was obtained with departmental protocol and diffusion-weighted sequences. The clinical data was collected from medical records and functional outcome was assessed at the time of admission using Barthel Index (BI) which was dichotomized into poor and favorable outcomes. The radiological data was collected and three infarct patterns (cortical, subcortical, and territorial infarcts) were recorded from diffusion-weighted images. Association of other risk factors such as age, gender, diabetes, hypertension (HTN), hyperlipidemia, and smoking were also evaluated. Results Amongst the three infarct patterns, subcortical infarcts were noted with the highest proportion of 62% (67/108). The highest proportion of territorial infarcts (78.6%) was significantly associated with a poor outcome in comparison to cortical and subcortical infarcts. Cortical infarcts (61.5%) were significantly associated with good outcomes followed by subcortical and then territorial infarcts (p-value < 0.002). Amongst the risk factors, HTN was found to be highly prevalent followed by diabetes mellitus (DM). Conclusion Subcortical infarct pattern was the most common, followed by territorial and cortical infarct. The highest proportion of infarct pattern with good outcomes was seen with cortical infarcts followed by subcortical and then territorial infarct pattern. HTN and coronary artery disease (CAD) were the effect modifiers showing significant association with poor outcomes.

Pulmonary hyperpolarized (129) Xe morphometry for mapping xenon gas concentrations and alveolar oxygen partial pressure: Proof-of-concept demonstration in healthy and COPD subjects.

PubMed

Ouriadov, A; Farag, A; Kirby, M; McCormack, D G; Parraga, G; Santyr, G E

2015-12-01

Diffusion-weighted (DW) hyperpolarized (129) Xe morphometry magnetic resonance imaging (MRI) can be used to map regional differences in lung tissue micro-structure. We aimed to generate absolute xenon concentration ([Xe]) and alveolar oxygen partial pressure (pA O2 ) maps by extracting the unrestricted diffusion coefficient (D0 ) of xenon as a morphometric parameter. In this proof-of-concept demonstration, morphometry was performed using multi b-value (0, 12, 20, 30 s/cm(2) ) DW hyperpolarized (129) Xe images obtained in four never-smokers and four COPD ex-smokers. Morphometric parameters and D0 maps were computed and the latter used to generate [Xe] and pA O2 maps. Xenon concentration phantoms estimating a range of values mimicking those observed in vivo were also investigated. Xenon D0 was significantly increased (P = 0.035) in COPD (0.14 ± 0.03 cm(2) /s) compared with never-smokers (0.12 ± 0.02 cm(2) /s). COPD ex-smokers also had significantly decreased [Xe] (COPD = 8 ± 7% versus never-smokers = 13 ± 8%, P = 0.012) and increased pA O2 (COPD = 18 ± 3% versus never-smokers = 15 ± 3%, P = 0.009) compared with never-smokers. Phantom measurements showed the expected dependence of D0 on [Xe] over the range of concentrations anticipated in vivo. DW hyperpolarized (129) Xe MRI morphometry can be used to simultaneously map [Xe] and pA O2 in addition to providing micro-structural biomarkers of emphysematous destruction in COPD. Phantom measurements of D0 ([Xe]) supported the hypotheses that differences in subjects may reflect differences in functional residual capacity. © 2014 Wiley Periodicals, Inc.

Triggered intravoxel incoherent motion MRI for the assessment of calf muscle perfusion during isometric intermittent exercise.

PubMed

Mastropietro, Alfonso; Porcelli, Simone; Cadioli, Marcello; Rasica, Letizia; Scalco, Elisa; Gerevini, Simonetta; Marzorati, Mauro; Rizzo, Giovanna

2018-06-01

The main aim of this paper was to propose triggered intravoxel incoherent motion (IVIM) imaging sequences for the evaluation of perfusion changes in calf muscles before, during and after isometric intermittent exercise. Twelve healthy volunteers were involved in the study. The subjects were asked to perform intermittent isometric plantar flexions inside the MRI bore. MRI of the calf muscles was performed on a 3.0 T scanner and diffusion-weighted (DW) images were obtained using eight different b values (0 to 500 s/mm 2 ). Acquisitions were performed at rest, during exercise and in the subsequent recovery phase. A motion-triggered echo-planar imaging DW sequence was implemented to avoid movement artifacts. Image quality was evaluated using the average edge strength (AES) as a quantitative metric to assess the motion artifact effect. IVIM parameters (diffusion D, perfusion fraction f and pseudo-diffusion D*) were estimated using a segmented fitting approach and evaluated in gastrocnemius and soleus muscles. No differences were observed in quality of IVIM images between resting state and triggered exercise, whereas the non-triggered images acquired during exercise had a significantly lower value of AES (reduction of more than 20%). The isometric intermittent plantar-flexion exercise induced an increase of all IVIM parameters (D by 10%; f by 90%; D* by 124%; fD* by 260%), in agreement with the increased muscle perfusion occurring during exercise. Finally, IVIM parameters reverted to the resting values within 3 min during the recovery phase. In conclusion, the IVIM approach, if properly adapted using motion-triggered sequences, seems to be a promising method to investigate muscle perfusion during isometric exercise. Copyright © 2018 John Wiley & Sons, Ltd.

Characterizing focal hepatic lesions by free-breathing intravoxel incoherent motion MRI at 3.0 T.

PubMed

Watanabe, Haruo; Kanematsu, Masayuki; Goshima, Satoshi; Kajita, Kimihiro; Kawada, Hiroshi; Noda, Yoshifumi; Tatahashi, Yukichi; Kawai, Nobuyuki; Kondo, Hiroshi; Moriyama, Noriyuki

2014-12-01

Diffusion-weighted (DW) imaging is commonly used to distinguish between benign and malignant liver lesions. To prospectively evaluate the true molecular-diffusion coefficient (D), perfusion-related diffusion coefficient (D*), perfusion fraction (f), and ADC of focal hepatic lesions using a free-breathing intravoxel incoherent motion (IVIM) DW sequence, and to determine if these parameters are useful for characterizing focal hepatic lesions. One hundred and twenty hepatic lesions (34 metastases, 32 hepatocellular carcinoma [HCC], 33 hemangiomas, and 21 liver cysts) in 74 patients were examined. Mean D, D*, f, and ADC values of hepatic lesions were compared among pathologies. ROC curve analyses were performed to assess the performances of D, D*, f, and ADC values for the characterization of liver lesions as benign or malignant. The mean D and ADC values of benign lesions were greater than those of malignant lesions (P < 0.001). Although the mean D and ADC values of liver cysts were greater than those of hemangiomas (P < 0.001), and these values were not significantly different between metastases and HCCs (P = 0.99). Area under the ROC curve for ADC values (0.98) was significantly greater (P = 0.048) than that for D values (0.96) for the differentiation of benign and malignant lesions. Sensitivity and specificity for the detection of malignant lesion were 89% and 98%, respectively, when an ADC cut-off value of 1.40 was applied. D and ADC values have more potential for characterizing focal hepatic lesions than D* or f values, and for the differentiation of malignancy and benignity. © The Foundation Acta Radiologica 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Arsenic hazards to humans, plants, and animals from gold mining

USGS Publications Warehouse

Eisler, R.

2004-01-01

Arsenic sources to the biosphere associated with gold mining include waste soil and rocks, residual water from ore concentrations, roasting of some types of gold-containing ores to remove sulfur and sulfur oxides, and bacterially-enhanced leaching. Arsenic concentrations near gold mining operations were elevated in abiotic materials and biota: maximum total arsenic concentrations measured were 560 ug/L in surface waters, 5.16 mg/L in sediment pore waters, 5.6 mg/kg dry weight (DW) in bird liver, 27 mg/kg DW in terrestrial grasses, 50 mg/kg DW in soils, 79 mg/kg DW in aquatic plants, 103 mg/kg DW in bird diets, 225 mg/kg DW in soft parts of bivalve molluscs, 324 mg/L in mine drainage waters, 625 mg/kg DW in aquatic insects, 7700 mg/kg DW in sediments, and 21,000 mg/kg DW in tailings. Single oral doses of arsenicals that were fatal to 50% of tested species ranged from 17 to 48 mg/kg body weight (BW) in birds and from 2.5 to 33 mg/kg BW in mammals. Susceptible species of mammals were adversely affected at chronic doses of 1 to 10 mg As/kg BW, or 50 mg As/kg diet. Sensitive aquatic species were damaged at water concentrations of 19 to 48 ug As/L, 120 mg As/kg diet, or tissue residues (in the case of freshwater fish) >1.3 mg/kg fresh weight. Adverse effects to crops and vegetation were recorded at 3 to 28 mg of water-soluble As/L (equivalent to about 25 to 85 mg total As/kg soil) and at atmospheric concentrations >3.9 ug As/m3. Gold miners had a number of arsenic-associated health problems including excess mortality from cancer of the lung, stomach, and respiratory tract. Miners and schoolchildren in the vicinity of gold mining activities had elevated urine arsenic of 25.7 ug/L (range 2.2-106.0 ug/L). Of the total population at this location, 20% showed elevated urine arsenic concentrations associated with future adverse health effects; arsenic-contaminated drinking water is the probable causative factor of elevated arsenic in urine. Proposed arsenic criteria to protect human health and natural resources are listed and discussed. Many of these proposed criteria do not adequately protect sensitive species.

WE-G-18C-02: Estimation of Optimal B-Value Set for Obtaining Apparent Diffusion Coefficient Free From Perfusion in Non-Small Cell Lung Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Karki, K; Hugo, G; Ford, J

2014-06-15

Purpose: Diffusion-weighted MRI (DW-MRI) is increasingly being investigated for radiotherapy planning and response assessment. Selection of a limited number of b-values in DW-MRI is important to keep geometrical variations low and imaging time short. We investigated various b-value sets to determine an optimal set for obtaining monoexponential apparent diffusion coefficient (ADC) close to perfusion-insensitive intravoxel incoherent motion (IVIM) model ADC (ADC IVIM) in nonsmall cell lung cancer. Methods: Seven patients had 27 DW-MRI scans before and during radiotherapy in a 1.5T scanner. Respiratory triggering was applied to the echo-planar DW-MRI with TR=4500ms approximately, TE=74ms, pixel size=1.98X1.98mm{sub 2}, slice thickness=4–6mm andmore » 7 axial slices. Diffusion gradients were applied to all three axes producing traceweighted images with eight b-values of 0–1000μs/μm{sup 2}. Monoexponential model ADC values using various b-value sets were compared to ADC IVIM using all b-values. To compare the relative noise in ADC maps, intra-scan coefficient of variation (CV) of active tumor volumes was computed. Results: ADC IVIM, perfusion coefficient and perfusion fraction for tumor volumes were in the range of 880-1622 μm{sup 2}/s, 8119-33834 μm{sup 2}/s and 0.104–0.349, respectively. ADC values using sets of 250, 800 and 1000; 250, 650 and 1000; and 250–1000μs/μm{sup 2} only were not significantly different from ADC IVIM(p>0.05, paired t-test). Error in ADC values for 0–1000, 50–1000, 100–1000, 250–1000, 500–1000, and three b-value sets- 250, 500 and 1000; 250, 650 and 1000; and 250, 800 and 1000μs/μm{sup 2} were 15.0, 9.4, 5.6, 1.4, 11.7, 3.7, 2.0 and 0.2% relative to the reference-standard ADC IVIM, respectively. Mean intrascan CV was 20.2, 20.9, 21.9, 24.9, 32.6, 25.8, 25.4 and 24.8%, respectively, whereas that for ADC IVIM was 23.3%. Conclusion: ADC values of two 3 b-value sets (250, 650 and 1000; and 250, 800 and 1000μs/μm{sup 2}) approached ADC IVIM, with relative noise comparable to that of ADC IVIM. These sets may be used to obtain perfusion-insensitive ADC values in lung tumors. E. Weiss: Funding through Varian Medical Systems and Philips Oncology Systems, UpToDate royalties. G. Hugo: NIH R01CA166119, P01 CA116602, NHMRC Project Grant.« less

Diffusion-weighted magnetic resonance imaging of femoral head osteonecrosis in two groups of patients: Legg-Perthes-Calve and Avascular necrosis.

PubMed

Ozel, Betul Duran; Ozel, Deniz; Ozkan, Fuat; Halefoglu, Ahmet M

2016-03-01

The aim of this prospective study was to evaluate the value of diffusion-weighted magnetic resonance imaging (DW-MRI) in patients with osteonecrosis. Patients were divided into two subgroups as avascular necrosis (AVN) of femoral head for adult group and Legg-Calvé-Perthes (LCP) patients for children. Seventeen patients with femoral head AVN (mean age 42.3 years) and 17 patients with LCP (mean age 8.2 years) were included in this study. Diagnosis confirmed with clinical and other imaging procedures among the patients complaining hip pain. DW images were obtained using the single-shot echo planar sequence and had b values of 0, 500, 1000 s/mm(2). The apparent diffusion coefficient (ADC) values were measured from ADC maps in epiphysis of patients with AVN, both from metaphysis and epiphysis in patients with LCP, respectively. Mann-Whitney U test was used to compare ADC values. The mean ADC value of femoral heads (1.285 ± 0.204 × 10(-3) mm(2)/s) was increased in patients with AVN when compared to normal bone tissue (0.209 ± 0.214 × 10(-3) mm(2)/s) (p < 0.01). The mean ADC values (×10(-3) mm(2)/s) of both metaphysis (0.852 ± 0.293) and epiphysis (0.843 ± 0.332) were also increased in patients with LCP and differences were statistically significant (p < 0.01). As a result, osteonecrosis shows increased ADC values. But it is a controversial concept that DWI offers a valuable data to conventional MRI or not. However, as there are report states, there is a correlation between the stage of the disease with ADC values in the LCP disease. DWI is a fast, without-contrast administration technique and provides quantitative values additional to conventional MR techniques; we believe DWI may play an additional assistance to the diagnosis and treatment for LCP patients. Multicentric larger group studies may provide additional data to this issue.

Evaluation of cholesteatoma: our experience with DW Propeller imaging.

PubMed

Karandikar, Amit; Loke, Siu Cheng; Goh, Julian; Yeo, Seng Beng; Tan, Tiong Yong

2015-09-01

Cholesteatoma management includes early detection and surgical exploration. Due to its tendency to recur, it can be potentially locally aggressive. Magnetic resonance imaging (MRI), and in particular diffusion weighted imaging (DWI), plays an important role in management of these lesions. To assess the accuracy of Propeller (Periodically Rotated Overlapping ParallEL Lines with Enhanced Reconstruction) DW sequence in detecting middle ear and mastoid cholesteatomas in non-operated ears by surgical correlation. A retrospective review of 15 patients was done who underwent Propeller DWI with either clinically confirmed or suspected cholesteatomas. Surgical correlation was done in all cases. All patients had hyperintense foci on Propeller DWI. Surgical correlation performed revealed that 13 patients had cholesteatomas while two patients had mastoid abscesses. The location, extent, and size of cholesteatomas on Propeller DWI matched with the operative findings. Of the 13 patients with cholesteatomas, three patients had multiple foci of hyperintensity on Propeller DWI, which corroborated with the surgical finding of multiple cholesteatomas. The average apparent diffusion coefficient value of cholesteatoma was 0.868 × 10(-3) mm(2)/s, found to be higher than that of abscess, which was 0.425 × 10(-3) mm(2)/s. Propeller DWI was accurate in assessing the location, extent, and size of cholesteatomas as corroborated with surgical findings. Propeller DWI is useful in detecting number of cholesteatoma foci, a vital finding as it may impact the choice of surgery. © The Foundation Acta Radiologica 2014.

Validating the absolute reliability of a fat free mass estimate equation in hemodialysis patients using near-infrared spectroscopy.

PubMed

Kono, Kenichi; Nishida, Yusuke; Moriyama, Yoshihumi; Taoka, Masahiro; Sato, Takashi

2015-06-01

The assessment of nutritional states using fat free mass (FFM) measured with near-infrared spectroscopy (NIRS) is clinically useful. This measurement should incorporate the patient's post-dialysis weight ("dry weight"), in order to exclude the effects of any change in water mass. We therefore used NIRS to investigate the regression, independent variables, and absolute reliability of FFM in dry weight. The study included 47 outpatients from the hemodialysis unit. Body weight was measured before dialysis, and FFM was measured using NIRS before and after dialysis treatment. Multiple regression analysis was used to estimate the FFM in dry weight as the dependent variable. The measured FFM before dialysis treatment (Mw-FFM), and the difference between measured and dry weight (Mw-Dw) were independent variables. We performed Bland-Altman analysis to detect errors between the statistically estimated FFM and the measured FFM after dialysis treatment. The multiple regression equation to estimate the FFM in dry weight was: Dw-FFM = 0.038 + (0.984 × Mw-FFM) + (-0.571 × [Mw-Dw]); R(2)  = 0.99). There was no systematic bias between the estimated and the measured values of FFM in dry weight. Using NIRS, FFM in dry weight can be calculated by an equation including FFM in measured weight and the difference between the measured weight and the dry weight. © 2015 The Authors. Therapeutic Apheresis and Dialysis © 2015 International Society for Apheresis.

A study of T2-weighted MR image texture features and diffusion-weighted MR image features for computer-aided diagnosis of prostate cancer

NASA Astrophysics Data System (ADS)

Peng, Yahui; Jiang, Yulei; Antic, Tatjana; Giger, Maryellen L.; Eggener, Scott; Oto, Aytekin

2013-02-01

The purpose of this study was to study T2-weighted magnetic resonance (MR) image texture features and diffusionweighted (DW) MR image features in distinguishing prostate cancer (PCa) from normal tissue. We collected two image datasets: 23 PCa patients (25 PCa and 23 normal tissue regions of interest [ROIs]) imaged with Philips MR scanners, and 30 PCa patients (41 PCa and 26 normal tissue ROIs) imaged with GE MR scanners. A radiologist drew ROIs manually via consensus histology-MR correlation conference with a pathologist. A number of T2-weighted texture features and apparent diffusion coefficient (ADC) features were investigated, and linear discriminant analysis (LDA) was used to combine select strong image features. Area under the receiver operating characteristic (ROC) curve (AUC) was used to characterize feature effectiveness in distinguishing PCa from normal tissue ROIs. Of the features studied, ADC 10th percentile, ADC average, and T2-weighted sum average yielded AUC values (+/-standard error) of 0.95+/-0.03, 0.94+/-0.03, and 0.85+/-0.05 on the Phillips images, and 0.91+/-0.04, 0.89+/-0.04, and 0.70+/-0.06 on the GE images, respectively. The three-feature combination yielded AUC values of 0.94+/-0.03 and 0.89+/-0.04 on the Phillips and GE images, respectively. ADC 10th percentile, ADC average, and T2-weighted sum average, are effective in distinguishing PCa from normal tissue, and appear robust in images acquired from Phillips and GE MR scanners.

Subclinical ischemic events in patients undergoing carotid artery stent placement: comparison of proximal and distal protection techniques.

PubMed

Aytac, Emrah; Gürkaş, Erdem; Akpinar, Cetin Kursad; Saleem, Muhammad A; Qureshi, Adnan I

2017-10-01

To determine the relative effectiveness of proximal and distal protection in prevention of cerebral ischemic events during carotid artery stent (CAS) placement using diffusion-weighted MRI (DW-MRI). We analyzed data from patients who had undergone DW-MRI before and within 24 hours of CAS for symptomatic internal carotid artery (ICA) stenosis (with last ischemic events within 3 months). The study was performed prospectively; patients were not randomized, and were treated either with a proximal balloon occlusion system (Mo.Ma; Invatec, Roncadelle, Italy) or filter-type distal protection device (Spider device; ev3, Plymouth, Minnesota, USA). Of the 45 patients (mean age±SD: 66.9±9.8 years; 73.3% were men) who underwent CAS, 19 had proximal protection and 26 distal protection. New ischemic lesions were detected in 26/45 patients on DW-MRI scans obtained within 24 hours after CAS. The proportion of patients with new lesions on DW-MRI at 24 hours was not different between the two groups (47.4% vs 65.4% for proximal and distal protection, respectively). The mean number of new ischemic lesions on post-CAS DW-MRI was non-significantly higher in patients who underwent CAS with distal protection (2.80±3.54 for proximal protection vs 4.96±5.11 for distal protection; p=0.12). The proportion of patients with new lesions >1 cm did not differ between the two groups (5.3% for proximal protection vs 11.5% for distal protection; p=0.62). There was no difference in the rates of ischemic stroke between patients who underwent CAS treatment using proximal and distal protection (5.3% vs 7.7%; p=1.000). We found a relatively high rate of new ischemic lesions in patients undergoing CAS with cerebral protection. There was no difference in the proportion of patients with new lesions between patients treated using distal protection and those treated using proximal protection. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Demonstration of Nonlinearity Bias in the Measurement of the Apparent Diffusion Coefficient in Multicenter Trials

PubMed Central

Malyarenko, Dariya; Newitt, David; Wilmes, Lisa; Tudorica, Alina; Helmer, Karl G.; Arlinghaus, Lori R.; Jacobs, Michael A.; Jajamovich, Guido; Taouli, Bachir; Yankeelov, Thomas E.; Huang, Wei; Chenevert, Thomas L.

2015-01-01

Purpose Characterize system-specific bias across common magnetic resonance imaging (MRI) platforms for quantitative diffusion measurements in multicenter trials. Methods Diffusion weighted imaging (DWI) was performed on an ice-water phantom along the superior-inferior (SI) and right-left (RL) orientations spanning ±150 mm. The same scanning protocol was implemented on 14 MRI systems at seven imaging centers. The bias was estimated as a deviation of measured from known apparent diffusion coefficient (ADC) along individual DWI directions. The relative contributions of gradient nonlinearity, shim errors, imaging gradients and eddy currents were assessed independently. The observed bias errors were compared to numerical models. Results The measured systematic ADC errors scaled quadratically with offset from isocenter, and ranged between −55% (SI) and 25% (RL). Nonlinearity bias was dependent on system design and diffusion gradient direction. Consistent with numerical models, minor ADC errors (±5%) due to shim, imaging and eddy currents were mitigated by double echo DWI and image co-registration of individual gradient directions. Conclusion The analysis confirms gradient nonlinearity as a major source of spatial DW bias and variability in off-center ADC measurements across MRI platforms, with minor contributions from shim, imaging gradients and eddy currents. The developed protocol enables empiric description of systematic bias in multicenter quantitative DWI studies. PMID:25940607

Groupwise Registration and Atlas Construction of 4th-Order Tensor Fields Using the ℝ+ Riemannian Metric*

PubMed Central

Barmpoutis, Angelos

2010-01-01

Registration of Diffusion-Weighted MR Images (DW-MRI) can be achieved by registering the corresponding 2nd-order Diffusion Tensor Images (DTI). However, it has been shown that higher-order diffusion tensors (e.g. order-4) outperform the traditional DTI in approximating complex fiber structures such as fiber crossings. In this paper we present a novel method for unbiased group-wise non-rigid registration and atlas construction of 4th-order diffusion tensor fields. To the best of our knowledge there is no other existing method to achieve this task. First we define a metric on the space of positive-valued functions based on the Riemannian metric of real positive numbers (denoted by ℝ+). Then, we use this metric in a novel functional minimization method for non-rigid 4th-order tensor field registration. We define a cost function that accounts for the 4th-order tensor re-orientation during the registration process and has analytic derivatives with respect to the transformation parameters. Finally, the tensor field atlas is computed as the minimizer of the variance defined using the Riemannian metric. We quantitatively compare the proposed method with other techniques that register scalar-valued or diffusion tensor (rank-2) representations of the DWMRI. PMID:20436782

Demonstration of nonlinearity bias in the measurement of the apparent diffusion coefficient in multicenter trials.

PubMed

Malyarenko, Dariya I; Newitt, David; J Wilmes, Lisa; Tudorica, Alina; Helmer, Karl G; Arlinghaus, Lori R; Jacobs, Michael A; Jajamovich, Guido; Taouli, Bachir; Yankeelov, Thomas E; Huang, Wei; Chenevert, Thomas L

2016-03-01

Characterize system-specific bias across common magnetic resonance imaging (MRI) platforms for quantitative diffusion measurements in multicenter trials. Diffusion weighted imaging (DWI) was performed on an ice-water phantom along the superior-inferior (SI) and right-left (RL) orientations spanning ± 150 mm. The same scanning protocol was implemented on 14 MRI systems at seven imaging centers. The bias was estimated as a deviation of measured from known apparent diffusion coefficient (ADC) along individual DWI directions. The relative contributions of gradient nonlinearity, shim errors, imaging gradients, and eddy currents were assessed independently. The observed bias errors were compared with numerical models. The measured systematic ADC errors scaled quadratically with offset from isocenter, and ranged between -55% (SI) and 25% (RL). Nonlinearity bias was dependent on system design and diffusion gradient direction. Consistent with numerical models, minor ADC errors (± 5%) due to shim, imaging and eddy currents were mitigated by double echo DWI and image coregistration of individual gradient directions. The analysis confirms gradient nonlinearity as a major source of spatial DW bias and variability in off-center ADC measurements across MRI platforms, with minor contributions from shim, imaging gradients and eddy currents. The developed protocol enables empiric description of systematic bias in multicenter quantitative DWI studies. © 2015 Wiley Periodicals, Inc.

Changes in multimodality functional imaging parameters early during chemoradiation predict treatment response in patients with locally advanced head and neck cancer.

PubMed

Wong, Kee H; Panek, Rafal; Dunlop, Alex; Mcquaid, Dualta; Riddell, Angela; Welsh, Liam C; Murray, Iain; Koh, Dow-Mu; Leach, Martin O; Bhide, Shreerang A; Nutting, Christopher M; Oyen, Wim J; Harrington, Kevin J; Newbold, Kate L

2018-05-01

To assess the optimal timing and predictive value of early intra-treatment changes in multimodality functional and molecular imaging (FMI) parameters as biomarkers for clinical remission in patients receiving chemoradiation for head and neck squamous cell carcinoma (HNSCC). Thirty-five patients with stage III-IVb (AJCC 7th edition) HNSCC prospectively underwent 18 F-FDG-PET/CT, and diffusion-weighted (DW), dynamic contrast-enhanced (DCE) and susceptibility-weighted MRI at baseline, week 1 and week 2 of chemoradiation. Patients with evidence of persistent or recurrent disease during follow-up were classed as non-responders. Changes in FMI parameters at week 1 and week 2 were compared between responders and non-responders with the Mann-Whitney U test. The significance threshold was set at a p value of <0.05. There were 27 responders and 8 non-responders. Responders showed a greater reduction in PET-derived tumor total lesion glycolysis (TLG 40% ; p = 0.007) and maximum standardized uptake value (SUV max ; p = 0.034) after week 1 than non-responders but these differences were absent by week 2. In contrast, it was not until week 2 that MRI-derived parameters were able to discriminate between the two groups: larger fractional increases in primary tumor apparent diffusion coefficient (ADC; p < 0.001), volume transfer constant (K trans ; p = 0.012) and interstitial space volume fraction (V e ; p = 0.047) were observed in responders versus non-responders. ADC was the most powerful predictor (∆ >17%, AUC 0.937). Early intra-treatment changes in FDG-PET, DW and DCE MRI-derived parameters are predictive of ultimate response to chemoradiation in HNSCC. However, the optimal timing for assessment with FDG-PET parameters (week 1) differed from MRI parameters (week 2). This highlighted the importance of scanning time points for the design of FMI risk-stratified interventional studies.

Upweighting rare favourable alleles increases long-term genetic gain in genomic selection programs.

PubMed

Liu, Huiming; Meuwissen, Theo H E; Sørensen, Anders C; Berg, Peer

2015-03-21

The short-term impact of using different genomic prediction (GP) models in genomic selection has been intensively studied, but their long-term impact is poorly understood. Furthermore, long-term genetic gain of genomic selection is expected to improve by using Jannink's weighting (JW) method, in which rare favourable marker alleles are upweighted in the selection criterion. In this paper, we extend the JW method by including an additional parameter to decrease the emphasis on rare favourable alleles over the time horizon, with the purpose of further improving the long-term genetic gain. We call this new method dynamic weighting (DW). The paper explores the long-term impact of different GP models with or without weighting methods. Different selection criteria were tested by simulating a population of 500 animals with truncation selection of five males and 50 females. Selection criteria included unweighted and weighted genomic estimated breeding values using the JW or DW methods, for which ridge regression (RR) and Bayesian lasso (BL) were used to estimate marker effects. The impacts of these selection criteria were compared under three genetic architectures, i.e. varying numbers of QTL for the trait and for two time horizons of 15 (TH15) or 40 (TH40) generations. For unweighted GP, BL resulted in up to 21.4% higher long-term genetic gain and 23.5% lower rate of inbreeding under TH40 than RR. For weighted GP, DW resulted in 1.3 to 5.5% higher long-term gain compared to unweighted GP. JW, however, showed a 6.8% lower long-term genetic gain relative to unweighted GP when BL was used to estimate the marker effects. Under TH40, both DW and JW obtained significantly higher genetic gain than unweighted GP. With DW, the long-term genetic gain was increased by up to 30.8% relative to unweighted GP, and also increased by 8% relative to JW, although at the expense of a lower short-term gain. Irrespective of the number of QTL simulated, BL is superior to RR in maintaining genetic variance and therefore results in higher long-term genetic gain. Moreover, DW is a promising method with which high long-term genetic gain can be expected within a fixed time frame.

Development of hydrophilic dental wax without surfactant using a non-thermal air atmospheric pressure plasma jet

NASA Astrophysics Data System (ADS)

Lee, Jung-Hwan; Kim, Yong-Hee; Choi, Eun-Ha; Kim, Kwang-Mahn; Kim, Kyoung-Nam

2014-06-01

Dental wax (DW), a low-melting and high-molecular-weight organic mixture, is widely used in dentistry for forming moulds of teeth. Hydrophilicity is an important property for DW, as a wet dental investment is used to surround the wax before wax burnout is performed. However, recent attempts to improve the hydrophilicity of DW using a surfactant have resulted in the reduced mechanical properties of the dental investment, leading to the failure of the dental restoration. This study applied a non-thermal air atmospheric pressure plasma jet (AAPPJ) for DW surface treatment and investigated its effect on both DW hydrophilicity and the dental investment's mechanical properties. The results showed that the application of the AAPPJ significantly improved the hydrophilicity of the DW, and that the results were similar to that of cleaner-treated DW using commercially available products with surfactant. A surface chemical analysis indicated that the improvement of hydrophilicity was related to an increase in the number of oxygen-related bonds on the DW surface following the removal of carbon hydrate in both AAPPJ and cleaner-treated DW. However, cleaner treatment compromised the mechanical property of the dental investment when the dental investment was in contact with the treated DW, while the AAPPJ treatment did not. Therefore, the use of AAPPJ to treat DW is a promising method for accurate dental restoration, as it induces an improvement in hydrophilicity without harming the dental investment.

Assessment/Review of Methanol Technology and Utilization as a Fuel.

DTIC Science & Technology

1982-07-01

1981. 32. Owens, E.C., Naegeli , D.W., "Use of Low Molecular Weight Alcohols as Diesel Fuel Extenders (Proposal)," U.S. Army Fuels and Lubricants...34Potential Funding of R&D on Use of Alcohol as Aircraft Fuel," February 4, 1981. 38. Naegeli , D.W., "Dissociated Methanol as an Engine Fuel," Southwest...825-828, 1974. 41. Marbach, H.W., Jr., Owens, E.C., Ryan, T.W., Frame, E.A., Naegeli , D.W., "Evaluation of the effects of Alcohol Fuels on Spark

Randomized comparison of distal and proximal cerebral protection during carotid artery stenting.

PubMed

Cano, Manuel N; Kambara, Antônio M; de Cano, Silvia J F; Pezzi Portela, Luiz Antônio; Paes, Ângela Tavares; Costa, J Ribamar; Abizaid, Alexandre Antônio Cunha; Moreira, Samuel Martins; Sousa, Amanda G M R; Sousa, J Eduardo Moraes Rego

2013-11-01

This study sought to randomly compare cerebral protection with ANGIOGUARD (Cordis Corporation, Bridgewater, New Jersey) with Mo.Ma (Invatec/Medtronic Vascular Inc, Santa Rosa, California) during carotid artery stenting (CAS), using diffusion-weighted magnetic resonance imaging (DW-MRI) to detect new ischemic cerebral lesions. The number, size, and location of lesions were analyzed. The choice of the type of cerebral protection during CAS is controversial. From July 2008 to July 2011, 60 patients undergoing CAS were randomized to ANGIOGUARD or Mo.Ma, distributed by chance, 30 patients for each group. All patients underwent DW-MRI before and after CAS. An independent neuroradiologist blinded to the cerebral protection used analyzed the images. Univariate and multivariate logistic models were fitted to analyze new ischemic lesions. Alternatively, a propensity score approach was used to reduce the bias due to differences between the groups. For the number of lesions, we used Poisson regression models. New ischemic lesions seen on DW-MRI were present in 63.3% of the ANGIOGUARD group versus 66.7% of the Mo.Ma cohort (p = 0.787). The number of ischemic cerebral lesions per patient, when present, was significantly lower in the Mo.Ma group (a median of 6 lesions per patient vs. a median of 10 in the ANGIOGUARD, p < 0.001). Most lesions were small (<0.5 mm) and localized in the ipsilateral territory. One patient in the ANGIOGUARD group had a minor stroke during CAS (1.66%). New ischemic lesions seen on DW-MRI were present in both groups in >60%, but the number of lesions per patient was greater in the ANGIOGUARD group. No death or disabling stroke occurred during at least 1 year of follow-up in both cohorts. Copyright © 2013 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Incidence and predictors of silent embolic cerebral infarction following diagnostic coronary angiography.

PubMed

Kim, In-Cheol; Hur, Seung-Ho; Park, Nam-Hee; Jun, Dong-Hwan; Cho, Yun-Kyeong; Nam, Chang-Wook; Kim, Hyungseop; Han, Seong-Wook; Choi, Sae-Young; Kim, Yoon-Nyun; Kim, Kwon-Bae

2011-04-14

Coronary angiography (CAG) is an invasive diagnostic procedure, which could lead to procedure related complications. One of the well known post-procedural complications is cerebral embolic infarction with or without symptoms. Silent embolic cerebral infarction (SECI) has clinical significance because it can progress to a decline in cognitive function and increase the risk of dementia in the long term. The aim of this study was to detect the incidence and predictors of SECI after diagnostic CAG using diffusion-weighted magnetic resonance imaging (DW-MRI). A total of 197 patients with coronary artery disease who underwent DW-MRI for evaluation of intracranial vasculopathy before coronary artery bypass graft surgery were retrospectively enrolled in the present study. DW-MRI was performed within 48 h after diagnostic CAG. SECI was diagnosed as presence of focal bright high signal intensity in DW-MRI. Patients were divided into groups according to presence/absence of SECI (+ SECI vs. - SECI, respectively). The clinical and angiographic characteristics were analyzed and independent predictors were evaluated. Of the 197 patients, SECI occurred in 20 patients (10.2%) after diagnostic CAG. Age, female gender, frequency of underlying atrial fibrillation, extent of coronary disease, and fluoroscopic time during diagnostic CAG were not different between the + SECI and - SECI groups. Left ventricular ejection fraction was significantly lower in the + SECI group than in the - SECI group (45.9 ± 8.5% vs. 51.4 ± 13.1%, p=0.014) and performance rate of internal mammary artery (IMA) angiography was significantly higher in the + SECI group compared with the - SECI group (85% vs. 37.2%, p<0.001). By multivariate analysis, performing IMA angiography was the only predictor of SECI (OR=14.642; 95% CI=3.201 to 66.980, p=0.001). The incidence of SECI after diagnostic CAG was not infrequent. Diagnostic CAG with IMA angiography may increase the risk of SECI. Copyright © 2009 Elsevier Ireland Ltd. All rights reserved.

Depth-dependence and monthly variability of charophyte biomass production: consequences for the precipitation of calcium carbonate in a shallow Chara-lake.

PubMed

Pukacz, Andrzej; Pełechaty, Mariusz; Frankowski, Marcin

2016-11-01

The month-to-month variability of biomass and CaCO 3 precipitation by dense charophyte beds was studied in a shallow Chara-lake at two depths, 1 and 3 m. Charophyte dry weights (d.w.), the percentage contribution of calcium carbonate to the dry weight and the precipitation of CaCO 3 per 1 m 2 were analysed from May to October 2011. Physical-chemical parameters of water were also measured for the same sample locations. The mean dry weight and calcium carbonate precipitation were significantly higher at 1 m than at 3 m. The highest measured charophyte dry weight (exceeding 2000 g m -2 ) was noted at 1 m depth in September, and the highest CaCO 3 content in the d.w. (exceeding 80 % of d.w.) was observed at 3 m depth in August. The highest CaCO 3 precipitation per 1 m 2 exceeded 1695 g at 1 m depth in August. Significant differences in photosynthetically active radiation (PAR) were found between 1 and 3 m depths; there were no significant differences between depths for other water properties. At both sampling depths, there were distinct correlations between the d.w., CaCO 3 content and precipitation and water properties. In addition to PAR, the water temperature and magnesium and calcium ion concentrations were among the most significant determinants of CaCO 3 content and d.w. The results show that light availability seems to be the major factor in determining charophyte biomass in a typical, undisturbed Chara-lake. The study results are discussed in light of the role of charophyte vegetation in whole ecosystem functioning, with a particular focus on sedimentary processes and the biogeochemical cycle within the littoral zone.

Concentrations of polybrominated diphenyl ethers and alternative flame retardants in surface soils and river sediments from an electronic waste-processing area in northern Vietnam, 2012-2014.

PubMed

Matsukami, Hidenori; Suzuki, Go; Someya, Masayuki; Uchida, Natsuyo; Tue, Nguyen Minh; Tuyen, Le Huu; Viet, Pham Hung; Takahashi, Shin; Tanabe, Shinsuke; Takigami, Hidetaka

2017-01-01

We investigated the concentrations of polybrominated diphenyl ethers (PBDEs) and alternative flame retardants (FRs) in environmental samples collected in January 2012, 2013, and 2014 from an electronic waste-processing area in northern Vietnam. During the study period, PBDE and alternative FR concentrations in soils around the electronic waste-processing workshops ranged from 37 to 9200 ng g -1 dry weight (dw) and from 35 to 24,000 ng g -1 dw; the concentrations in soils around the open-burning sites ranged from 1.6 to 62 ng g -1 dw and from <4 to 1900 ng g -1 dw; and the concentrations in river sediments around the workshops ranged from 100 to 3800 ng g -1 dw and from 23 to 6800 ng g -1 dw, respectively. Over the course of study period, we observed significant decreases in concentrations of PBDEs and significant increases in concentrations of alternative FRs, particularly Dechlorane Plus isomers and oligomeric organophosphorus FRs (o-PFRs) in both soils and sediments around the workshops. We also report information on concentrations and environmental emissions of o-PFRs and their low-molecular-weight impurities in the same soils and sediments. The detection of o-PFR impurities around the workshops and the open-burning sites highlights an enhanced breakdown of o-PFRs probably due to weathering during open storage and high temperature attained during the burning of electronic wastes. Copyright © 2016 Elsevier Ltd. All rights reserved.

Anomalous diffusion on the Hanoi networks

NASA Astrophysics Data System (ADS)

Boettcher, S.; Gonçalves, B.

2008-11-01

Diffusion is modeled on the recently proposed Hanoi networks by studying the mean-square displacement of random walks with time, langr2rang~t2/dw. It is found that diffusion —the quintessential mode of transport throughout Nature— proceeds faster than ordinary, in one case with an exact, anomalous exponent dw=2- log2(phi)=1.30576... . It is an instance of a physical exponent containing the "golden ratio"\\phi=(1+\\sqrt{5})/2 that is intimately related to Fibonacci sequences and since Euclid's time has been found to be fundamental throughout geometry, architecture, art, and Nature itself. It originates from a singular renormalization group fixed point with a subtle boundary layer, for whose resolution phi is the main protagonist. The origin of this rare singularity is easily understood in terms of the physics of the process. Yet, the connection between network geometry and the emergence of phi in this context remains elusive. These results provide an accurate test of recently proposed universal scaling forms for first passage times.

Parental and perinatal factors affecting childhood anthropometry of very-low-birth-weight premature infants: a population-based survey.

PubMed

Makhoul, Imad R; Awad, Eman; Tamir, Ada; Weintraub, Zalman; Rotschild, Avi; Bader, David; Yurman, Shmuel; Reich, Dan; Bental, Yoram; Jammalieh, Jeryes; Smolkin, Tatiana; Sujov, Polo; Hochberg, Ze'ev

2009-06-01

The perinatal-neonatal course of very-low-birth-weight (VLBW) infants might affect their childhood growth. We evaluated the effect of parental anthropometry and perinatal and neonatal morbidity of VLBW neonates on their childhood growth. We obtained parental anthropometry, height and weight at age 6-10.5 years of 334 children born as VLBW infants. Parental, perinatal and neonatal data of these children were tested for association with childhood anthropometry. (1) Maternal and paternal weight standard deviation score (SDS) and discharge weight (DW) SDS were associated with childhood weight SDS (R(2)= 0.111, p < 0.00001); (2) Maternal and paternal height SDS, corrected gestational age (GA) at discharge, maternal assisted reproduction and SGA status were associated with childhood height SDS (R(2)= 0.208, p < 0.00001); (3) paternal weight SDS, DW SDS and surfactant therapy were associated with childhood body mass index (BMI) SDS (R(2)= 0.096, p < 0.00001). 31.1% of VLBW infants had DW SDS < -1.88, and are to be considered small for gestational age ('SGA'). One quarter of these infants did not catch up by age 6-10.5 years. Childhood anthropometry of VLBW infants depends on parental anthropometry, postnatal respiratory morbidity and growth parameters at birth and at discharge. Almost one-third of VLBW premature infants had growth restriction at discharge from neonatal intensive care unit (NICU), a quarter of whom did not catch up by age 6-10.5 years.

Phytochemical profiles and antioxidant activity of 27 cultivars of tea.

PubMed

Zeng, Liang; Luo, Liyong; Li, Hongjun; Liu, Ruihai

2017-08-01

Tea, rich in phytochemicals, has been suggested to have human health benefits. The phenolic profiles, antioxidant and antiproliferative activities of 27 tea cultivars were determined. Wide ranges of variation were found in analyzed cultivars for the contents of water-soluble phenolics (121.6-223.7 mg/g dry weight (DW)), total catechins (TC) (90.5-177.2 mg/g DW), antioxidant activities (PSC values 627.3-2332.3 μmol of vitamin C equiv/g DW, ORAC values (1865.1-3489.3 μmol of vitamin C equiv/g DW), CAA values (37.7-134.3 μmol of QE/g DW without PBS wash and 25.3-75.4 μmol of QE/g DW with PBS wash) and antiproliferative activity (53.0-90.8% at the concentration of 400 μg/mL extracts). The PSC, ORAC and CAA values were significantly correlated with phenolics, epicatechin gallate (ECG), CC and TC. Knowledge of specific differences among tea cultivars is important for breeding tea cultivars and gives sights to its potential application to promote health.

Growth chart

MedlinePlus

... while standing up in children over age 3) Head circumference , a measurement of the head size taken by ... carefully. Alternative Names Height and weight chart Images Head circumference Height/weight chart References Cooke DW, Dival SA, ...

Early changes in the apparent diffusion coefficient and MMP-9 expression of a cervical carcinoma U14 allograft model following irradiation.

PubMed

Huang, Yecai; Huang, Jianming; Feng, Mei; Ren, Jing; Mi, Kun; Cheng, Jia; Song, Bing; Lang, Jinyi

2017-12-01

A cervical carcinoma allograft model was designed to assess the correlation between early changes in the apparent diffusion coefficient (ADC) values on diffusion-weighted magnetic resonance imaging (DW-MRI) and the expression of matrix metalloproteinase-9 (MMP-9) in tumors. BALB/c mice with U14 tumor allografts on the right rear flank were irradiated with a single 20 Gy dose. All tumor-bearing mice were subjected to DW-MRI, followed by calculation of the ADC values and characterization of the T1 and T2 relaxation time constants. Pre- and post-irradiation ADC values were compared with the tumor volume, and the immunohistochemical staining of MMP-9 and hematoxylin-eosin (HE) staining of tumor allografts. However, no correlations between the pre-treatment ADC values and changes in tumor volumes following irradiation were observed. Notably, the mean ADC value was significantly higher in the irradiated tumors (0.756±0.102×10 -3 mm 2 /sec) as compared with those in the untreated tumors (0.501±0.052×10 -3 mm 2 /sec; P=0.002; r=0.682). Additionally, immunohistochemical staining demonstrated that MMP-9 expression in the irradiated tumors was significantly increased. The mean ADC value was significantly higher in the irradiated tumors with high MMP-9 expression levels (0.815±0.112×10 -3 mm 2 /sec), as compared with in the untreated tumors with low MMP-9 expression levels (0.631±0.068×10 -3 mm 2 /sec). Quantitative analysis determined that the ADC values were correlated with MMP-9 expression (r=0.752; P=0.003). Combined, these results suggest that radiation-induced increases in MMP-9 expression levels may be responsible for early changes in the mean ADC value and the response to irradiation in cervical carcinoma.

An estimation framework for building information modeling (BIM)-based demolition waste by type.

PubMed

Kim, Young-Chan; Hong, Won-Hwa; Park, Jae-Woo; Cha, Gi-Wook

2017-12-01

Most existing studies on demolition waste (DW) quantification do not have an official standard to estimate the amount and type of DW. Therefore, there are limitations in the existing literature for estimating DW with a consistent classification system. Building information modeling (BIM) is a technology that can generate and manage all the information required during the life cycle of a building, from design to demolition. Nevertheless, there has been a lack of research regarding its application to the demolition stage of a building. For an effective waste management plan, the estimation of the type and volume of DW should begin from the building design stage. However, the lack of tools hinders an early estimation. This study proposes a BIM-based framework that estimates DW in the early design stages, to achieve an effective and streamlined planning, processing, and management. Specifically, the input of construction materials in the Korean construction classification system and those in the BIM library were matched. Based on this matching integration, the estimates of DW by type were calculated by applying the weight/unit volume factors and the rates of DW volume change. To verify the framework, its operation was demonstrated by means of an actual BIM modeling and by comparing its results with those available in the literature. This study is expected to contribute not only to the estimation of DW at the building level, but also to the automated estimation of DW at the district level.

Thinned stone fruits are a source of polyphenols and antioxidant compounds.

PubMed

Redondo, Diego; Arias, Esther; Oria, Rosa; Venturini, María E

2017-02-01

Thinned fruits are agricultural by-products that contain large quantities of interesting compounds due to their early maturity stage. In this work, the phenolic profile and the antioxidant activity of six thinned stone fruits (apricot, cherry, flat peach, peach, plum and nectarine) have been investigated, focussing on proanthocyanidins. Thinned nectarine had the highest content of total phenols [67.43 mg gallic acid equivalents (GAE) g -1 dry weight (DW)] and total flavonoids (56.97 mg CE g -1 DW) as well as the highest antioxidant activity measured by DPPH scavenging (133.30 mg [Trolox equivalents (TE) g -1 DW] and FRAP assay (30.42 mg TE g -1 DW). Proanthocyanidins were very abundant in these by-products, and the main phenolic group quantified in cherry (10.54 mg g -1 DW), flat peach (33.47 mg g -1 DW) and nectarine (59.89 mg g -1 DW), while hydroxycinnamic acids predominate in apricot, peach and plum (6.67, 22.04 and 23.75 mg g -1 DW, respectively). The low, mean degree of polymerisation of proanthocyanidins suggests that their bioavailability could be very high. This study shows that thinned stone fruit extracts might be used as antioxidants in foods or as a source of compounds with health-related benefits that can be used in the pharmaceutical, cosmetic and food industries. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Temporal variation in fish mercury concentrations within lakes from the western Aleutian Archipelago, Alaska

USGS Publications Warehouse

Kenney, Leah A.; Eagles-Smith, Collin A.; Ackerman, Joshua T.; von Hippel, Frank A.

2014-01-01

We assessed temporal variation in mercury (Hg) concentrations of threespine stickleback (Gasterosteus aculeatus) from Agattu Island, Aleutian Archipelago, Alaska. Total Hg concentrations in whole-bodied stickleback were measured at two-week intervals from two sites in each of two lakes from June 1 to August 10, 2011 during the time period when lakes were ice-free. Across all sites and sampling events, stickleback Hg concentrations ranged from 0.37–1.07 µg/g dry weight (dw), with a mean (± SE) of 0.55±0.01 µg/g dw. Mean fish Hg concentrations declined by 9% during the study period, from 0.57±0.01 µg/g dw in early June to 0.52±0.01 µg/g dw in mid-August. Mean fish Hg concentrations were 6% higher in Loon Lake (0.56±0.01 µg/g dw) than in Lake 696 (0.53±0.01 µg/g dw), and 4% higher in males (0.56±0.01 µg/g dw) than in females (0.54±0.01 µg/g dw). Loon Lake was distinguished from Lake 696 by the presence of piscivorous waterbirds during the breeding season. Mercury concentrations in stickleback from Agattu Island were higher than would be expected for an area without known point sources of Hg pollution, and high enough to be of concern to the health of piscivorous wildlife.

The Phenolic Contents and Antioxidant Activities of Infusions of Sambucus nigra L.

PubMed

Viapiana, Agnieszka; Wesolowski, Marek

2017-03-01

The aim of this work was to evaluate the antioxidant potential of teas prepared from twenty-four commercially available berries and flowers of Sambucus nigra L. in relation to their phenolic profile, as reflected by the most representative phenolic acids (caffeic, chlorogenic, p-coumaric, ferulic, gallic and syringic acids); flavonols (quercetin, kaempferol, myricetin and rutin); and total phenolic (TPC), phenolic acid (TAC) and flavonoid (TFC) contents. The infusions prepared from elderflowers contained more abundant phenolic compounds than the elderberry infusions. The TPC of these infusions ranged from 19.81 to 23.90 mg of gallic acid equivalents/g dry weight of sample (GAE/g DW) for elderberries and from 15.23 to 35.57 mg GAE/g DW for elderflowers, whereas the TFC ranged from 2.60 to 4.49 mg of rutin equivalents/g dry weight of sample (RUTE/g DW) in elderberry infusions and from 5.27 to 13.19 mg RUTE/g DW in elderflower infusions. Among the phenolic compounds quantified in this study, quercetin (2.07-9.48 mg/g DW) and myricetin (1.17-9.62 mg/g DW) had the highest concentrations in the teas prepared from berries and flowers, respectively. Moreover, the antioxidant potential of elder infusions assessed by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and ferric reducing antioxidant power (FRAP) assays revealed that the teas prepared from flowers had higher mean DPPH and FRAP activities than the teas prepared from berries. Therefore, elder beverages could be important dietary sources of natural antioxidants that contribute to the prevention of diseases caused by oxidative stress.

Imaging biomarkers to monitor response to the hypoxia-activated prodrug TH-302 in the MiaPaCa2 flank xenograft model.

PubMed

Cárdenas-Rodríguez, Julio; Li, Yuguo; Galons, Jean-Philippe; Cornnell, Heather; Gillies, Robert J; Pagel, Mark D; Baker, Amanda F

2012-09-01

TH-302, a hypoxia-activated anticancer prodrug, was evaluated for antitumor activity and changes in dynamic contrast-enhanced (DCE) and diffusion-weighted (DW) magnetic resonance imaging (MRI) in a mouse model of pancreatic cancer. TH-302 monotherapy resulted in a significant delay in tumor growth compared to vehicle-treated controls. TH-302 treatment was also associated with a significant decrease in the volume transfer constant (K(trans)) compared to vehicle-treated controls 1 day following the first dose measured using DCE-MRI. This early decrease in K(trans) following the first dose as measured is consistent with selective killing of the hypoxic fraction of cells which are associated with enhanced expression of hypoxia inducible transcription factor-1 alpha that regulates expression of permeability and perfusion factors including vascular endothelial growth factor-A. No changes were observed in DW-MRI following treatment with TH-302, which may indicate that this technique is not sensitive enough to detect changes in small hypoxic fractions of the tumor targeted by TH-302. These results suggest that changes in tumor permeability and/or perfusion may be an early imaging biomarker for response to TH-302 therapy. Copyright © 2012 Elsevier Inc. All rights reserved.

Tree bark as a biomonitor for the determination of polychlorinated biphenyls and polybrominated diphenyl ethers from Southern Jiangsu, China: levels, distribution, and possible sources.

PubMed

Zhou, Li; Dong, Liang; Huang, Ye-Ru; Shi, Shuang-Xin; Zhang, Li-Fei; Zhang, Xiu-Lan; Yang, Wen-Long

2015-09-01

Tree bark was used as the passive air sampler to evaluate polychlorinated biphenyl (PCB) and polybrominated diphenyl ether (PBDE) pollution and possible sources in Southern Jiangsu. The concentrations of PCBs and Σ7PBDEs were in the range of 0.58-5.19 ng/g dry weight (dw; mean 1.79 ng/g dw) and 17.9-243 pg/g dw (mean 74.7 pg/g dw), respectively. Tri-PCBs were the major PCB homologs, and technical PCB product Ar1242 was identified as the main source. BDE209 concentrations (4.29-456 ng/g dw) were relatively high, indicating that BDE209 pollution was serious in this region. The deca-BDE commercial mixture was the predominant commercial PBDE product used in this region. A good correlation was found between tree bark and polyurethane foam (PUF) disks in Σ6PCB monitoring, suggesting that both of them respond well to the gas-phase PCB monitoring.

DCE-MRI, DW-MRI, and MRS in Cancer: Challenges and Advantages of Implementing Qualitative and Quantitative Multi-parametric Imaging in the Clinic

PubMed Central

Winfield, Jessica M.; Payne, Geoffrey S.; Weller, Alex; deSouza, Nandita M.

2016-01-01

Abstract Multi-parametric magnetic resonance imaging (mpMRI) offers a unique insight into tumor biology by combining functional MRI techniques that inform on cellularity (diffusion-weighted MRI), vascular properties (dynamic contrast-enhanced MRI), and metabolites (magnetic resonance spectroscopy) and has scope to provide valuable information for prognostication and response assessment. Challenges in the application of mpMRI in the clinic include the technical considerations in acquiring good quality functional MRI data, development of robust techniques for analysis, and clinical interpretation of the results. This article summarizes the technical challenges in acquisition and analysis of multi-parametric MRI data before reviewing the key applications of multi-parametric MRI in clinical research and practice. PMID:27748710

Analysis of phase error effects in multishot diffusion-prepared turbo spin echo imaging

PubMed Central

Cervantes, Barbara; Kooijman, Hendrik; Karampinos, Dimitrios C.

2017-01-01

Background To characterize the effect of phase errors on the magnitude and the phase of the diffusion-weighted (DW) signal acquired with diffusion-prepared turbo spin echo (dprep-TSE) sequences. Methods Motion and eddy currents were identified as the main sources of phase errors. An analytical expression for the effect of phase errors on the acquired signal was derived and verified using Bloch simulations, phantom, and in vivo experiments. Results Simulations and experiments showed that phase errors during the diffusion preparation cause both magnitude and phase modulation on the acquired data. When motion-induced phase error (MiPe) is accounted for (e.g., with motion-compensated diffusion encoding), the signal magnitude modulation due to the leftover eddy-current-induced phase error cannot be eliminated by the conventional phase cycling and sum-of-squares (SOS) method. By employing magnitude stabilizers, the phase-error-induced magnitude modulation, regardless of its cause, was removed but the phase modulation remained. The in vivo comparison between pulsed gradient and flow-compensated diffusion preparations showed that MiPe needed to be addressed in multi-shot dprep-TSE acquisitions employing magnitude stabilizers. Conclusions A comprehensive analysis of phase errors in dprep-TSE sequences showed that magnitude stabilizers are mandatory in removing the phase error induced magnitude modulation. Additionally, when multi-shot dprep-TSE is employed the inconsistent signal phase modulation across shots has to be resolved before shot-combination is performed. PMID:28516049

Using Chelator-Buffered Nutrient Solutions to Induce Ni-Deficiency in the Ni-Hyperaccumulator Alyssum murale

USDA-ARS?s Scientific Manuscript database

Ni is essential for all plants due to its role in urease. Many Alyssum species are known to hyperaccumulate Ni to over 20 g kg-1 dry weight (DW) while normal plants require only about 0.1 mg kg-1 DW. As part of our research on Ni hyperaccumulation by plants, we conducted experiments to measure the...

Magnetic resonance enterography versus capsule endoscopy activity indices for quantification of small bowel inflammation in Crohn’s disease

PubMed Central

Kopylov, Uri; Klang, Eyal; Yablecovitch, Doron; Lahat, Adi; Avidan, Benjamin; Neuman, Sandra; Levhar, Nina; Greener, Tomer; Rozendorn, Noa; Beytelman, Arkadi; Yanai, Henit; Dotan, Iris; Chowers, Yehuda; Weiss, Batya; Ben-Horin, Shomron; Amitai, Marianne M.; Eliakim, Rami

2016-01-01

Background: Video capsule endoscopy (VCE) and magnetic resonance enterography (MRE) are the prime modalities for the evaluation of small bowel (SB) Crohn’s disease (CD). Mucosal inflammation on VCE is quantified using the Lewis score (LS). Diffusion-weighted (DW) magnetic resonance imaging (MRI) allows for accurate assessment of SB inflammation without administration of intravenous contrast material. The Magnetic Resonance Index of Activity (MaRiA) and the Clermont index are quantitative activity indices validated for contrast-enhanced MRE and DW-MRE, respectively. The aim of this study was to compare the quantification of distal SB inflammation by VCE and MR-related activity indices. Methods: Patients with known quiescent SB CD were prospectively recruited and underwent MRE and VCE. LS, MaRIA and Clermont scores were calculated for the distal SB. Results: Both MRI-based indices significantly correlated with the LS and the Clermont index (r = 0.50, p = 0.001 and r = 0.53, p = 0.001, respectively). Both MaRIA and Clermont scores were significantly lower in patients with mucosal healing (LS < 135). The area under the curve (AUC) with both MR scores was moderate for prediction of any mucosal inflammation (LS ⩾ 135) and excellent for prediction of moderate-to-severe inflammation (LS ⩾ 790) (0.71 and 0.74 versus 0.93 and 0.91 for MaRIA and Clermont score, respectively). Conclusions: Modest correlation between VCE- and MRE-based quantitative indices of inflammation in patients with quiescent SB CD was observed. Between-modality correlation was higher in patients with endoscopically severe disease. DW-MRE gauged by Clermont score was at least as accurate as contrast-enhanced MRE for quantification of SB inflammation. PMID:27582877

Optimal Parameters to Determine the Apparent Diffusion Coefficient in Diffusion Weighted Imaging via Simulation

NASA Astrophysics Data System (ADS)

Perera, Dimuthu

Diffusion weighted (DW) Imaging is a non-invasive MR technique that provides information about the tissue microstructure using the diffusion of water molecules. The diffusion is generally characterized by the apparent diffusion coefficient (ADC) parametric map. The purpose of this study is to investigate in silico how the calculation of ADC is affected by image SNR, b-values, and the true tissue ADC. Also, to provide optimal parameter combination depending on the percentage accuracy and precision for prostate peripheral region cancer application. Moreover, to suggest parameter choices for any type of tissue, while providing the expected accuracy and precision. In this research DW images were generated assuming a mono-exponential signal model at two different b-values and for known true ADC values. Rician noise of different levels was added to the DWI images to adjust the image SNR. Using the two DWI images, ADC was calculated using a mono-exponential model for each set of b-values, SNR, and true ADC. 40,000 ADC data were collected for each parameter setting to determine the mean and the standard-deviation of the calculated ADC, as well as the percentage accuracy and precision with respect to the true ADC. The accuracy was calculated using the difference between known and calculated ADC. The precision was calculated using the standard-deviation of calculated ADC. The optimal parameters for a specific study was determined when both the percentage accuracy and precision were minimized. In our study, we simulated two true ADCs (ADC 0.00102 for tumor and 0.00180 mm2/s for normal prostate peripheral region tissue). Image SNR was varied from 2 to 100 and b-values were varied from 0 to 2000s/mm2. The results show that the percentage accuracy and percentage precision were minimized with image SNR. To increase SNR, 10 signal-averagings (NEX) were used considering the limitation in total scan time. The optimal NEX combination for tumor and normal tissue for prostate peripheral region was 1: 9. Also, the minimum percentage accuracy and percentage precision were obtained when low b-value is 0 and high b-value is 800 mm2/s for normal tissue and 1400 mm2/s for tumor tissue. Results also showed that for tissues with 1 x 10-3 < ADC < 2.1 x 10-3 mm 2/s the parameter combination at SNR = 20, b-value pair 0, 800 mm 2/s with NEX = 1:9 can calculate ADC with a percentage accuracy of less than 2% and percentage precision of 6-8%. Also, for tissues with 0.6 x 10-3 < ADC < 1.25 x 10-3 mm2 /s the parameter combination at SNR = 20, b-value pair 0, 1400 mm 2/s with NEX =1:9 can calculate ADC with a percentage accuracy of less than 2% and percentage precision of 6-8%.

High status of mercury and selenium in false killer whales (Pseudorca crassidens, Owen 1846) stranded on Southern South America: A possible toxicological concern?

PubMed

Cáceres-Saez, Iris; Haro, Daniela; Blank, Olivia; Aguayo Lobo, Anelio; Dougnac, Catherine; Arredondo, Cristóbal; Cappozzo, H Luis; Guevara, Sergio Ribeiro

2018-05-01

The study was carried out to determine Hg and Se concentrations in false killer whales stranded on the Estrecho de Magallanes, Chile, South America. Tissue samples of five mature specimens were analyzed (two females and three males). Mean Hg concentration in liver 1068 (234) μg g -1 dry weight (DW) (standard deviation in parenthesis) was markedly higher than those in kidney 272 (152) μg g -1 DW, lung 423 (325) μg g -1 DW, spleen 725 (696) μg g -1 DW, muscle 118 (94) μg g -1 DW and testicle 18.0 (2.8) μg g -1 DW. Mean Se concentration in liver, 398 (75) μg g -1 DW, was higher than those in kidney 162 (69) μg g -1 DW, lung 128 (84) μg g -1 DW, spleen 268 (245) μg g -1 DW, muscle 47 (38) μg g -1 DW and testicle 25.4 (2.1) μg g -1 DW. Positive correlations were found between Hg and Se molar concentrations in muscle, lung, spleen and kidney. Molar ratio of Se/Hg in liver, lung and muscle were <1, but those in kidney and testicle were markedly >1 suggesting a Se protection against Hg toxicity. In all the examined specimens Hg values exceeded the toxic thresholds defined for hepatic damage in marine mammals, with Se/Hg molar ratios below 1 implying limited protective action of Se. Generally, our results showed that individuals are carrying a significant burden, reflecting a high exposure to this toxic metal. This constitutes the first report on Hg and Se levels for a large subantarctic odontocete in South America region, providing insights into their contamination status and with information to the understanding of possible impacts on wild populations. Copyright © 2018 Elsevier Ltd. All rights reserved.

Experimental Study of Nasopharyngeal Carcinoma Radionuclide Imaging and Therapy Using Transferred Human Sodium/Iodide Symporter Gene

PubMed Central

Zhong, Xing; Shi, Changzheng; Gong, Jian; Guo, Bin; Li, Mingzhu; Xu, Hao

2015-01-01

Purpose The aim of this study was to design a method of radionuclide for imaging and therapy of nasopharyngeal carcinoma (NPC) using the transferred human sodium/iodide symporter (hNIS) gene. Methods A stable NPC cell line expressing hNIS was established (CNE-2-hNIS). After 131I treatment, we detected proliferation and apoptosis of NPC cells, both in vitro and vivo. In vivo, the radioactivity of different organs of nude mice was counted and 99mTc imaging using SPECT was performed. The apparent diffusion coefficient (ADC) value changes of tumor xenografts were observed by diffusion-weighted magnetic resonance imaging (DW-MRI) within 6–24 days of 131I treatment. The correlation of ADC changes with apoptosis and proliferation was investigated. Post-treatment expression levels of P53, Bax, Bcl-2, Caspase-3, and Survivin proteins were detected by western blotting. Results 131I uptake was higher in CNE-2-hNIS than in CNE-2 cells. The proliferation and apoptosis rate decreased and increased respectively both in vitro and vivo in the experimental group after 131I treatment. The experimental group tumors accumulated 99mTc in vivo, leading to a good visualization by SPECT. DW-MRI showed that ADC values increased in the experimental group 6 days after treatment, while ADC values were positively and negatively correlated with the apoptotic and Ki-67 proliferation indices, respectively. After treatment, CNE-2-hNIS cells up-regulated the expression of P53 and Survivin proteins and activated Caspase-3, and down-regulated the expression of Bcl-2 proteins. Conclusions The radionuclide imaging and therapy technique for NPC hNIS-transfected cell lines can provide a new therapy strategy for monitoring and treatment of NPC. PMID:25615643

Genetic variation of carotenoids, vitamin E and phenolic compounds in Provitamin A biofortified maize.

PubMed

Muzhingi, Tawanda; Palacios-Rojas, Natalia; Miranda, Alejandra; Cabrera, Maria L; Yeum, Kyung-J; Tang, Guangwen

2017-02-01

Biofortified maize is not only a good vehicle for provitamin A carotenoids for vitamin A deficient populations in developing countries but also a source of vitamin E, tocochromanols and phenolic compounds, which have antioxidant properties. Using high-performance liquid chromatography and a total antioxidant performance assay, the present study analyzed the antioxidant variation and antioxidant activity of 36 provitamin A improved maize hybrids and one common yellow maize hybrid. The ranges of major carotenoids in provitamin A carotenoids biofortified maize were zeaxanthin [1.2-13.2 µg g -1 dry weight (DW)], β-cryptoxanthin (1.3-8.8 µg g -1 DW) and β-carotene (1.3-8.0 µg g -1 DW). The ranges of vitamin E compounds identified in provitamin A carotenoids biofortified maize were α-tocopherol (3.4-34.3 µg g -1 DW), γ-tocopherol (5.9-54.4 µg g -1 DW), α-tocotrienol (2.6-19.5 µg g -1 DW) and γ-tocotrienol (45.4 µg g -1 DW). The ranges of phenolic compounds were γ-oryzanol (0.0-0.8 mg g -1 DW), ferulic acid (0.4-3.6 mg g -1 DW) and p-coumaric acid (0.1-0.45 mg g -1 DW). There was significant correlation between α-tocopherol and cis isomers of β-carotene (P < 0.01). Tocotrienols were correlated with α-tocopherol and γ-oryzanol (P < 0.01). Genotype was significant in determining the variation in β-cryptoxanthin, β-carotene, α-tocopherol and γ-tocopherol contents (P < 0.01). A genotype × environment interaction was observed for γ-tocopherol content (P < 0.01). © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Comparison of Mineral Element Content in a Functional Food Maca (Lepidium meyenii Walp.) from Asia and South America.

PubMed

Zhang, Ji; Wang, Han-Mo; Zhao, Yan-Li; Zuo, Zhi-Tian; Wang, Yuan-Zhong; Jin, Hang

2015-01-01

Contents of eight mineral elements in maca (Lepidium meyenii Walp.) from China and Peru were determined by inductively coupled plasma optical emission spectroscopy. Cu contents in maca samples from China (2.5-31 mg kg(-1) dry weight, dw) were higher than the samples from Peru (<2.1 mg kg(-1) dw). Na in two samples from China was found to be significantly of high content (2400 and 2600 mg kg(-1) dw). The contents (mg kg(-1) dw) of B, Co, Cr, Li, Ni, and Zn were, respectively, 8.1-21, <0.023, <1.1~3.5, 0.020-0.17, 0.085-4.5, and 10-39 for the samples from China, while being 6.6-12, <0.023, <1.1~2.3, 0.035-0.063, 0.68-1.7, and 27-39 for the samples from Peru.

Can coca leaves contribute to improving the nutritional status of the Andean population?

PubMed

Penny, Mary E; Zavaleta, Alfonso; Lemay, Melanie; Liria, Maria Reyna; Huaylinas, Maria Luisa; Alminger, Marie; McChesney, James; Alcaraz, Franklin; Reddy, Manju B

2009-09-01

Coca leaves (Erythroxylum coca) have been promoted as a food that could address the dietary deficiencies of the Andean population, but this is based on nutrient analyses of a small sample of leaves. We assessed the nutritional potential of eight samples of coca leaves grown in different regions of Peru. We used AOAC techniques to measure nutrients, nutrient inhibitors (phytate, polyphenols, oxalic acid, and fiber), and alkaloid concentrations, all expressed per 100 g dry weight (DW) of the ground leaves. Minerals were measured by inductively coupled lasma- mass spectrometry in n twondependent laboratories. The leaves contained protein, , 20.28 g/1 0DW with lysine as the limiting amino acid; n-cbetarotene, 3.51 mg/100gDW ; vitamin E, 16.72 mg/100gDW ; trace amounts of vitamin D; calcium, 990.18 and 1033.17 mg/100 gDW at two different laboratories; iron, 29.16 and 29.16 mg/100 gDW; zinc, 2.71 and 2.63 mg/100 gDW; and magnesium, 225.19 and 196.69 mg/l001gDW Cocaine was the principal alkaloid, with a concentration of 0.56 g/100 gDW; other alkaloids were also identified. The results were compared with those for other edible leaves. The nutrient contributions of coca powder (5 g) and bread made with coca were compared with those of normal portions of alternative foods. Two spoonfuls of coca leaf flour would satisfy less than 10% of dietary intakes for schoolchildren and adults for critical commonly deficient nutrients in the diet. Coca leaves do not provide nutritional benefits when eaten in the recommended quantities, and the presence of absorbable cocaine and other alkaloids may be potentially harmful; hence coca leaves cannot be recommended as a food.

Comparison of anthropometric-based equations for estimation of body fat percentage in a normal-weight and overweight female cohort: validation via air-displacement plethysmography.

PubMed

Temple, Derry; Denis, Romain; Walsh, Marianne C; Dicker, Patrick; Byrne, Annette T

2015-02-01

To evaluate the accuracy of the most commonly used anthropometric-based equations in the estimation of percentage body fat (%BF) in both normal-weight and overweight women using air-displacement plethysmography (ADP) as the criterion measure. A comparative study in which the equations of Durnin and Womersley (1974; DW) and Jackson, Pollock and Ward (1980) at three, four and seven sites (JPW₃, JPW₄ and JPW₇) were validated against ADP in three groups. Group 1 included all participants, group 2 included participants with a BMI <25·0 kg/m² and group 3 included participants with a BMI ≥25·0 kg/m². Human Performance Laboratory, Institute for Sport and Health, University College Dublin, Republic of Ireland. Forty-three female participants aged between 18 and 55 years. In all three groups, the %BF values estimated from the DW equation were closer to the criterion measure (i.e. ADP) than those estimated from the other equations. Of the three JPW equations, JPW₃ provided the most accurate estimation of %BF when compared with ADP in all three groups. In comparison to ADP, these findings suggest that the DW equation is the most accurate anthropometric method for the estimation of %BF in both normal-weight and overweight females.

Support vector machine for breast cancer classification using diffusion-weighted MRI histogram features: Preliminary study.

PubMed

Vidić, Igor; Egnell, Liv; Jerome, Neil P; Teruel, Jose R; Sjøbakk, Torill E; Østlie, Agnes; Fjøsne, Hans E; Bathen, Tone F; Goa, Pål Erik

2018-05-01

Diffusion-weighted MRI (DWI) is currently one of the fastest developing MRI-based techniques in oncology. Histogram properties from model fitting of DWI are useful features for differentiation of lesions, and classification can potentially be improved by machine learning. To evaluate classification of malignant and benign tumors and breast cancer subtypes using support vector machine (SVM). Prospective. Fifty-one patients with benign (n = 23) and malignant (n = 28) breast tumors (26 ER+, whereof six were HER2+). Patients were imaged with DW-MRI (3T) using twice refocused spin-echo echo-planar imaging with echo time / repetition time (TR/TE) = 9000/86 msec, 90 × 90 matrix size, 2 × 2 mm in-plane resolution, 2.5 mm slice thickness, and 13 b-values. Apparent diffusion coefficient (ADC), relative enhanced diffusivity (RED), and the intravoxel incoherent motion (IVIM) parameters diffusivity (D), pseudo-diffusivity (D*), and perfusion fraction (f) were calculated. The histogram properties (median, mean, standard deviation, skewness, kurtosis) were used as features in SVM (10-fold cross-validation) for differentiation of lesions and subtyping. Accuracies of the SVM classifications were calculated to find the combination of features with highest prediction accuracy. Mann-Whitney tests were performed for univariate comparisons. For benign versus malignant tumors, univariate analysis found 11 histogram properties to be significant differentiators. Using SVM, the highest accuracy (0.96) was achieved from a single feature (mean of RED), or from three feature combinations of IVIM or ADC. Combining features from all models gave perfect classification. No single feature predicted HER2 status of ER + tumors (univariate or SVM), although high accuracy (0.90) was achieved with SVM combining several features. Importantly, these features had to include higher-order statistics (kurtosis and skewness), indicating the importance to account for heterogeneity. Our findings suggest that SVM, using features from a combination of diffusion models, improves prediction accuracy for differentiation of benign versus malignant breast tumors, and may further assist in subtyping of breast cancer. 3 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2018;47:1205-1216. © 2017 International Society for Magnetic Resonance in Medicine.

Environmental Assessment: Zebra Mussel Eradication from the Base Lake at Offutt Air Force Base

DTIC Science & Technology

2008-09-11

water flow even in large diameter piping, increase sedimentation rates , and promote surface corrosion. Natural populations of 5,000 to 30,000...Body Weight (kg) Foraging Territory (ha) Food Ingestion Rate (kg dw/day) Food Ingestion Rate (kg ww/day) Water (L/day) Sediment / Soil Ingestion...Composition - based on diets for Missouri; Korschgen (1958) in USEPA (1993) Soil/ Sediment Ingestion Rate – Assumed 1% of dw ingestion rate ; USEPA (2000

Mercury in alpine fish from four rivers in the Tibetan Plateau.

PubMed

Shao, Junjuan; Shi, Jianbo; Duo, Bu; Liu, Chengbin; Gao, Yan; Fu, Jianjie; Yang, Ruiqiang; Jiang, Guibin

2016-01-01

As a global pollutant, high levels of mercury (Hg) have been found in remote ecosystem due to the long range atmospheric transport. In this study, a total of 60 fish samples were collected from four rivers across the Tibetan Plateau to study the accumulation of Hg in remote and high-altitude aquatic environment. The total Hg (THg) and methylmercury (MeHg) in fish muscles ranged from 11 to 2097 ng/g dry weight (dw) (average: 819 ng/g dw) and from 14 to 1960 ng/g dw (average: 756 ng/g dw), respectively. Significantly positive linear relationships were observed between the THg (r=0.591, p<0.01, n=36) and MeHg concentrations (r=0.473, p<0.01, n=36) with the trophic level of fish from Lhasa River, suggesting trophic transfer and biomagnification of Hg in this aquatic ecosystem. Moreover, the THg levels in fish had significantly positive correlations with the length (r=0.316, p<0.05, n=60) and weight (r=0.271, p<0.05, n=60) of fish. The high levels of Hg were attributed to the slow growth and long lifespan of the fish under this sterile and cold environment. Risk assessment revealed that the consumption of Oxygymnocypris stewartii, Schizothorax macropogon, Schizothorax waltoni, Schizopygopsis younghusbandi and Schizothorax o'connori would lead to a high exposure to MeHg. Copyright © 2015. Published by Elsevier B.V.

Contaminant exposure of willets feeding in agricultural drainages of the lower Rio Grande valley of south Texas USA

USGS Publications Warehouse

Custer, T.W.; Mitchell, C.A.

1991-01-01

Willets (Catoptrophorus semipalmatus) were collected in June and August 1986 at the outlets of two agricultural drainages into the Lower Languna Madre of south Texas and at two other Texas coastal sites. Mean liver concentrations of arsenic was higher in August than June. Over 20% of the livers had arsenic concentrations elevated above a suggested background level of 5.0 ppm dry weight (DW), but concentrations (maximum 15 ppm) were below those associated with acute toxicity. Selenium concentration in livers varied from 2.3 to 8.3 ppm DW for all locations and represented background levels. Mercury concentrations in liver for all locations (mean = 2.0 to 3.4, maximum 17 ppm DW) were below those associated with avian mortality and similar to levels found in other estuarine/marine birds. DDE in carcasses was higher in adults (mean = 1.0 ppm wet weight) than juveniles (0.2 ppm), and higher in August (1.0 ppm) than June (0.5 ppm); however, DDE concentrations were generally at background levels. Based on brain cholinesterase activity, willets were not recently exposed to organophosphate pesticides.

Environmental contaminants in male river otters from Oregon and Washington, USA, 1994-1999

USGS Publications Warehouse

Grove, R.A.; Henny, C.J.

2008-01-01

This study reports hepatic concentrations and distribution patterns of select metals, organochlorine pesticides (OCs), polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in 180 male river otters (Lontra canadensis) collected from Oregon and Washington, 1994-1999. Seven regional locations of western Oregon and Washington were delineated based on associations with major population centers, industry or agriculture. Cadmium (Cd) was not found above 0.5 ??g g-1, dry weight (dw) in juveniles, but increased with age in adults though concentrations were generally low (nd-1.18 ??g g-1, dw). Regional geometric means for total mercury (THg) ranged from 3.63 to 8.05 ??g g-1, dw in juveniles and 3.46-2.6 ??g g-1 (dw) in adults. The highest THg concentration was 148 ??g g-1, dw from an apparently healthy adult male from the Olympic Peninsula of Washington. Although THg increased with age in adult otters, the occurrence of the more toxic form methylmercury (MeHg) was not evaluated. Mean OC and PCB concentrations reported in this study declined dramatically from those reported in 1978-1979 from the lower Columbia River. Organochlorine pesticide and metabolite means for both juvenile and adult river otter males were all below 100 ??g kg-1, wet weight (ww), with only DDE, DDD and HCB having individual concentrations exceeding 500 ??g kg-1, ww. Mean ??PCB concentrations in both juvenile and adult male otters were below 1 ??g g-1 for all regional locations. Mean juvenile and adult concentrations of non-ortho substituted PCBs, PCDDs and PCDFs were in the low ng kg-1 for all locations studied. ?? Springer Science+Business Media B.V. 2007.

Fresh from the Ornamental Garden: Hips of Selected Rose Cultivars Rich in Phytonutrients.

PubMed

Cunja, Vlasta; Mikulic-Petkovsek, Maja; Weber, Nika; Jakopic, Jerneja; Zupan, Anka; Veberic, Robert; Stampar, Franci; Schmitzer, Valentina

2016-02-01

Morphological parameters (size, weight, color), the content of sugars, organic acids, lycopene, β-carotene, and phenolics were determined in hips of Rosa canina (RCA), Rosa sweginzowii (RSW), Rosa rugosa (RUG), and selected ornamental Rosa cultivars Fru Dagmar Hastrup (FDH), Repandia (REP), Veilchenblau (RVB), Aloha (RAL), Bonica (BON), and Golden Gate (RGG). Although traditionally used RCA hips contained the highest amount of cyanidin-3-glucoside (83 μg/g DW) and were the reddest (h° = 17.5), they did not stand out in other analyzed parameters. RGG climber had the biggest hips (8.86 g), which also contained highest sugar levels (50.9 g/100 g DW). RAL stood out as the cultivar rich in organic acids (33.9 g/100 g DW), mainly because of high quinic acid content (17.6 g/100g DW). FDH and RSW hips were characterized by particularly high ascorbic acid levels (4325 mg/100 g DW and 4711 mg/100 g DW). Other ornamental cultivars contained low amounts of ascorbic acid compared to the analyzed species. The phenolic profile was species/cultivars-specific. The greatest diversity of phenolic compounds was detected in RUG and FDH hips (55 and 54 different tentatively identified compounds with HPLC/MS). Flavanols represented the main phenolic class in most of the investigated species/cultivars and RGG hips contained the highest amount of catechin and proanthocyandin derivatives (15855 μg/g DW). Altogether RAL hips contained the highest quantity of phenolics (44746 μg/g DW) mainly due to high levels of hydrolysable tannins compared to other species/cultivars. Although small, hips of BON and REP were most abundant regarding β-carotene and lycopene content, respectively. © 2016 Institute of Food Technologists®

Determination of the Sensibility Factors for TLD-100 Powder on the Energy of X-Ray of 50, 250 kVp; 192Ir, 137Cs and 60Co

DOE Office of Scientific and Technical Information (OSTI.GOV)

Loaiza, Sandra P.; Alvarez, Jose T.

2006-09-08

TLD-100 powder is calibrated in terms of absorbed dose to water Dw, using the protocols AAPM TG61, AAPM TG43 and IAEA-TRS 398, for the energy of RX 50, 250 kVp, 137Cs and 60Co respectively. The calibration curves, TLD Response R versus Dw, are fitted by weighted least square by a quadratic polynomials; which are validated with the lack of fit and the Anderson-Darling normality test. The slope of these curves corresponds to the sensibility factor: Fs R/DW, [Fs] = nC Gy-1. The expanded uncertainties U's for these factors are obtained from the ANOVA tables. Later, the Fs' values are interpolatedmore » using the effective energy hvefec for the 192Ir. The SSDL sent a set of capsules with powder TLD-100 for two Hospitals. These irradiated them a nominal dose of Dw = 2 Gy. The results determined at SSDL are: for the Hospital A the Dw is overestimated in order to 4.8% and the Hospital B underestimates it in the range from -1.4% to -17.5%.« less

Enhanced bacoside production in shoot cultures of Bacopa monnieri under the influence of abiotic elicitors.

PubMed

Sharma, Munish; Ahuja, Ashok; Gupta, Rajinder; Mallubhotla, Sharada

2015-01-01

The effect of different abiotic elicitors [jasmonic acid, copper sulphate (CuSO4) and salicyclic acid] at varying concentrations on the stimulation of biomass and bacoside production in in vitro Bacopa monnieri shoot culture was studied. A systematic study conducted over a period of 35 days indicated that the maximum bacoside production (6.74 mg g(-1) dry weight (DW)) was obtained after a lag of 7 days and thereafter, the content decreased gradually to again increase at 28 days (5.91 mg g(-1) DW). Therefore, elicitation experiments were carried out over a period of 3, 6 and 9 days. The shoot cultures treated with 45 mg L(-1) of CuSO4 exhibited the highest bacoside content of 8.73 mg g(-1) DW (∼1.42-fold higher) than in control cultures (6.14 mg g(-1) DW). This study indicates the effectiveness of abiotic elicitation on bacoside production in in vitro shoot cultures of this medicinally important herb known for its memory-enhancing properties.

Polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in harbor sediments from Sea Lots, Port-of-Spain, Trinidad and Tobago

USGS Publications Warehouse

Mohammed, Azad; Peterman, Paul; Echols, Kathy; Feltz, Kevin; Tegerdine, George; Manoo, Anton; Maraj, Dexter; Agard, John; Orazio, Carl

2011-01-01

Concentrations of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were determined in nearshore marine surficial sediments from three locations in Trinidad. Sediments were sampled at Sea Lots on the west coast, in south Port-of-Spain Harbor, south of Sea Lots at Caroni Lagoon National Park, and on Trinidad's east coast at Manzanilla. Total PCB concentrations in Sea Lots sediments ranged from 62 to 601 ng/g (dry weight {dw}), which was higher than at Caroni and Manzanilla, 13 and 8 ng/g dw, respectively. Total OCP concentrations at Sea Lots were ranged from 44.5 to 145 ng/g dw, compared with 13.1 and 23.8 n/g (dw), for Caroni and Manzanilla respectively. The concentrations of PCBs and of some OCPs in sediments from Sea Lots were above the Canadian interim sediment quality guidelines. To date, this data is the first report on the levels of PCBs and other organochlorine compounds from Trinidad and Tobago.

Comparison of Mineral Element Content in a Functional Food Maca (Lepidium meyenii Walp.) from Asia and South America

PubMed Central

Zhang, Ji; Wang, Han-Mo; Zhao, Yan-Li; Zuo, Zhi-Tian; Wang, Yuan-Zhong

2015-01-01

Contents of eight mineral elements in maca (Lepidium meyenii Walp.) from China and Peru were determined by inductively coupled plasma optical emission spectroscopy. Cu contents in maca samples from China (2.5–31 mg kg−1 dry weight, dw) were higher than the samples from Peru (<2.1 mg kg−1 dw). Na in two samples from China was found to be significantly of high content (2400 and 2600 mg kg−1 dw). The contents (mg kg−1 dw) of B, Co, Cr, Li, Ni, and Zn were, respectively, 8.1–21, <0.023, <1.1~3.5, 0.020–0.17, 0.085–4.5, and 10–39 for the samples from China, while being 6.6–12, <0.023, <1.1~2.3, 0.035–0.063, 0.68–1.7, and 27–39 for the samples from Peru. PMID:26236540

Enhanced production of azadirachtin by hairy root cultures of Azadirachta indica A. Juss by elicitation and media optimization.

PubMed

Satdive, Ramesh K; Fulzele, Devanand P; Eapen, Susan

2007-02-01

Azadirachtin is one of the most potent biopesticides so far developed from a plant sources. Influence of different culture media and elicitation on growth and production of azadirachtin by hairy root cultures of Azadirachta indica was studied. Out of the three media tested, namely Ohyama and Nitsch, Gamborg's and Murashige and Skoog's basal media, hairy roots cultured on Ohyama and Nitsch's basal medium produced maximum yield of azadirachtin (0.0166% dry weight, DW). Addition of biotic elicitor enhanced the production of azadirachtin by approximately 5-fold (0.074% DW), while signal compounds such as jasmonic acid and salicylic acid showed a approximately 6 (0.095% DW) and approximately 9-fold (0.14% DW) enhancement, respectively, in the production of azadirachtin as compared to control cultures on Ohyama and Nitsch medium. Extracts from hairy roots were found to be superior to those from the leaves for antifeedant activity against the larvae of Spodoptera litura.

Polonium-210 and Caesium-137 in lynx (Lynx lynx), wolverine (Gulo gulo) and wolves (Canis lupus).

PubMed

Gjelsvik, Runhild; Holm, Elis; Kålås, John Atle; Persson, Bertil; Asbrink, Jessica

2014-12-01

Wolves, lynx and wolverines are on the top of the food-chain in northern Scandinavia and Finland. (210)Po and (137)Cs have been analysed in samples of liver, kidney and muscle from 28 wolves from Sweden. In addition blood samples were taken from 27 wolves. In 9 of the wolves, samples of muscle, liver and blood were analysed for (210)Po. Samples of liver and muscle were collected from 16 lynx and 16 wolverines from Norway. The liver samples were analysed for (210)Po and (137)Cs. Only (137)Cs analyses were carried out for the muscle samples. The wolves were collected during the winter 2010 and 2011, while the samples for lynx and wolverines were all from 2011. The activity concentrations of (210)Po in wolves were higher for liver (range 20-523 Bq kg(-1) d.w.) and kidney (range 24-942 Bq kg(-1) d.w.) than muscle (range 1-43 Bq kg(-1) d.w.) and blood (range 2-54 Bq kg(-1) d.w.). Activity ratios, (210)Po/(210)Pb, in wolf samples of muscle, liver and blood were in the ranges 2-77, 9-56 and 2-54. Using a wet weight ratio of 3.8 the maximal absorbed dose from (210)Po to wolf liver was estimated to 3500 μGy per year. Compared to wolf, the ranges of (210)Po in liver samples were lower in lynx (range 22-211 Bq kg(-1) d.w.) and wolverine (range16-160 Bq kg(-1) d.w.). Concentration of (137)Cs in wolf samples of muscle, liver, kidney and blood were in the ranges 70-8410 Bq kg(-1) d.w., 36-4050 Bq kg(-1) d.w., 31-3453 Bq kg(-1) d.w. and 4-959 Bq kg(-1) d.w., respectively. (137)Cs in lynx muscle and liver samples were in the ranges 44-13393 Bq kg(-1) d.w. and 125-10260 Bq kg(-1) d.w. The corresponding values for (137)Cs in wolverine were 22-3405 Bq kg(-1) d.w. for liver and 53-4780 Bq kg(-1) d.w. for muscle. The maximal absorbed dose from (137)Cs to lynx was estimated to 3000 μGy per year. Copyright © 2014 Elsevier Ltd. All rights reserved.

Levels and sources of PAHs in selected sites from Portugal: biomonitoring with Pinus pinea and Pinus pinaster needles.

PubMed

Ratola, Nuno; Amigo, José Manuel; Alves, Arminda

2010-04-01

Pine needle samples from two pine species (Pinus pinaster Ait. and Pinus pinea L.) were collected at 29 sites scattered throughout Portugal, in order to biomonitor the levels and trends of 16 polycyclic aromatic hydrocarbons (PAHs). The values obtained for the sum of all PAHs ranged from 76 to 1944 ng/g [dry weight (dw)]. Despite the apparent matrix similarities between both pine species, P. pinaster needles revealed higher mean entrapment levels than P. pinea (748 and 399 ng/g (dw) per site, respectively). The urban and industrial sites have the highest average of PAH incidence [for P. pinea, 465 and 433 ng/g (dw) per site, respectively, and for P. pinaster, 1147 and 915 ng/g (dw)], followed by the rural sites [233 ng/g and 711 ng/g (dw) per site, for P. pinea and P. pinaster, respectively]. The remote sites, both from P. pinaster needles, show the least contamination, with 77 ng/g (dw) per site. A predominance of 3-ring and 4-ring PAHs was observed in most samples, with phenanthrene having 30.1% of the total. Naphthalene prevailed in remote sites. Rainfall had no influence on the PAHs levels, but there was a relationship between higher wind speeds and lower concentrations. PAH molecular ratios revealed the influence of both petrogenic and pyrogenic sources.

Organochlorine pesticides in tree bark and human hair in Yunnan Province, China: Concentrations, distributions and exposure pathway.

PubMed

Yuan, Haodong; Jin, Jun; Bai, Yao; Li, Qiuxu; Wang, Ying; Wang, Qinghua

2017-02-15

The concentrations and distributions of organochlorine pesticides (OCPs) in West China were investigated and internal and external exposure of humans to OCPs were assessed by analyzing samples of human hair and tree bark collected in Kaiyuan, in Yunnan Province, China. Dichlorodiphenyltrichloroethane and its metabolites (collectively called DDTs), hexachlorocyclohexanes (HCHs), and hexachlorobenzene (HCB) were the dominant OCPs in the human hair and tree bark samples. The mean total DDT, total HCH, and HCB concentrations in the tree bark samples were 298pg/g dry weight (dw), 100pg/g dw, and 183pg/g dw, respectively, and the mean total DDT, total HCH, and HCB concentrations in the hair samples were 2850pg/g dw, 348pg/g dw, and 1026pg/g dw, respectively. The results indicated that relatively new DDT and lindane inputs have occurred in the study area. DDT and lindane may have been released in products that are used locally. The HCB in the environment in the study area is mainly supplied by long-range atmospheric transport. External exposure was found to be the main factor controlling the p,p'-DDT, γ-HCH, and HCB concentrations in human hair, whereas p,p'-DDE and β-HCH were found to be mainly controlled by internal exposure. Copyright © 2016 Elsevier B.V. All rights reserved.

Prevalence of adherence to fluid restriction in kidney patients in haemodialysis: objective indicator and perceived compliance.

PubMed

Iborra-Moltó, Carmelo; López-Roig, Sofía; Pastor-Mira, M de Los Ángeles

2012-07-17

Studies of adherence to fluid restriction show high variability in prevalence data, as different methods of measuring IWG (interdialysis weight gain) and cut-off criteria are used. To describe the prevalence of adherence to fluid restriction using daily IWG (criterion: ≤1 Kg) and daily IWG adjusted for dry weight (DW) (cut-off point adjusted criterion: DW<70 kg, IWG=1 kg/day; DW>70 kg and ≤80 kg, IWG=1.1 kg/day; DW>80 kg and ≤90 kg, IWG=1.2 kg/day; DW>90 kg, IWG=1.3 kg/day) and to study the association between this objective indicator and adherence behaviour as reported by patient. Our study included a total of 146 patients with a mean age of 66 years (SD: 13.6 years; range: 25-88 years), 66% of which were male. Ours was a longitudinal study with one month of follow-up. We collected both sociodemographic and clinical variables and mean daily IWG. Patient-reported adherence behaviour was assessed through an interview by a trained staff member from outside the department who asked the following question: "In order to avoid complications between haemodialysis sessions: during the last month, how many days did you ingest less than 1 litre of fluid per day?" (0= no days; 10= every day). A score ≤5 led to categorisation of patients as compliant with treatment. Statistical analysis included descriptive analysis, correlation test, chi-square and Crosstabs, ROC curve and logistic regression procedures. Prevalence of "objective" adherence to fluid restriction was 61% (mean daily IWG≤1kg) and 73% (mean daily IWG adjusted for dry weight). Reported adherence (prevalence: 56.2%) was associated with IWG adjusted for weight (chi-square =31.34; P=.000). In patients with objective adherence adjusted for weight, the prevalence of reported adherence was 1.65 times that of non-adherence (PR=1.65; 95% CI: 1.29-2.11). The final model for estimating the association between reported adherence behaviour and daily adjusted IWG included: age (higher), dry weight (lower), potassium (lower), time on haemodialysis treatment (less) and its interaction with reported behaviour (F=50.70; P=.000; R2=44%). The sensitivity of reported adherence behaviour for detecting objective adherence adjusted for dry weight was 89%; specificity was 58%, and the overall classification power was 85% (AUC=.85; 95% CI: 0.78-0.92). The probability of objective adherence adjusted for weight in patients who claimed proper adherence was 9 times higher than in non-compliant patients in patients who had been on HD for 2.3 years (PORp25=9.16; 95% CI: 2.58-32.51); 6 times higher in patients on HD for 4.7 years (PORP50=6.16; 95% CI: 2.1217.92); and 3 times higher in those on HD for 8.2 years (PORp75=3.44; 95% CI: 1.32-8.96). Prevalence of adherence to fluid restriction was 73% and 16% depending on daily IWG adjusted/not adjusted for dry weight, respectively. Absolute daily IWG adjusted for weight seems a good indicator of adherence, as it allows for a personalised fluid restriction regimen. Significant association between this objective indicator and reported adherence behaviour supports a combination of patient approach and objective data, which can help with the adjustment of the individual cut-off for daily IWG. This also provides useful information for designing intervention strategies to maintain and increase adherence.

Diffusion-weighted magnetic resonance imaging to differentiate malignant from benign gallbladder disorders.

PubMed

Kitazume, Yoshio; Taura, Shin-Ichi; Nakaminato, Shuichiro; Noguchi, Osamu; Masaki, Yukiyoshi; Kasahara, Ichiro; Kishino, Mitsuhiro; Tateishi, Ukihide

2016-04-01

To retrospectively evaluate the utility of apparent diffusion coefficient (ADC) and lesion to spinal cord ratio (LSR) in diffusion-weighted magnetic resonance (MR) imaging (DWI) as compared with morphological assessment alone, for differentiating malignant from benign gallbladder disorders. This study was approved by the ethics committee, and written informed consent was waived. Ninety-one patients (13 malignancy and 78 benignancy) were reviewed. ADC was calculated using two DW images with different motion-probing gradient strengths (b=0, 1000s/mm(2)). LSR was measured by dividing the signal intensity of a thickened gallbladder wall by the maximum signal intensity of the lumbar enlargement of the spinal cord. In addition, the morphology of the gallbladders was assessed with conventional MR imaging. In receiver operating characteristic curve analysis, the areas under the curves for ADC and LSR were 0.861 and 0.906, respectively. Three morphological findings were considered: a massive formation, a disrupted mucosal line, and the absence of a two-layered pattern. When a combination of two or more of these morphological findings was positive for malignancy, the sensitivity, specificity, and accuracy were 76.9%, 84.0%, and 83.0%, respectively. When a combination of three or more of the above morphological findings together with ADC of less than 1.2 × 10(-3)mm(2)/s or LSR of more than 0.48 were positive for malignancy, these values were 73.0%, 96.2%, and 92.9%, respectively. There were significant differences in specificity and accuracy. Use of ADC and LSR in DWI can improve diagnostic performance for differentiating malignant from benign gallbladder disorders. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Lethal and sub-lethal effects of five pesticides used in rice farming on the earthworm Eisenia fetida.

PubMed

Rico, Andreu; Sabater, Consuelo; Castillo, María-Ángeles

2016-05-01

The toxicity of five pesticides typically used in rice farming (trichlorfon, dimethoate, carbendazim, tebuconazole and prochloraz) was evaluated on different lethal and sub-lethal endpoints of the earthworm Eisenia fetida. The evaluated endpoints included: avoidance behaviour after an exposure period of 2 days; and mortality, weight loss, enzymatic activities (cholinesterase, lactate dehydrogenase and alkaline phosphatase) and histopathological effects after an exposure period of 14 days. Carbendazim was found to be highly toxic to E. fetida (LC50=2mg/kg d.w.), significantly reducing earthworm weight and showing an avoidance response at soil concentrations that are close to those predicted in rice-fields and in surrounding ecosystems. The insecticide dimethoate showed a moderate acute toxicity (LC50=28mg/kg d.w.), whereas the rest of tested pesticides showed low toxicity potential (LC50 values above 100mg/kg d.w.). For these pesticides, however, weight loss was identified as a sensitive endpoint, with NOEC values approximately 2 times or lower than the calculated LC10 values. The investigated effects on the enzymatic activities of E. fetida and the observed histopathological alterations (longitudinal and circular muscle lesions, edematous tissues, endothelial degeneration and necrosis) proved to be sensitive biomarkers to monitor pesticide contamination and are proposed as alternative measures to evaluate pesticide risks on agro-ecosystems. Copyright © 2016 Elsevier Inc. All rights reserved.

Chemical composition, angiotensin-converting enzyme-inhibitory activity and antioxidant activities of few-flower wild rice (Zizania latifolia Turcz.).

PubMed

Qian, Bingjun; Luo, Yali; Deng, Yun; Cao, Linkui; Yang, Hongshun; Shen, Yongpei; Ping, Jian

2012-01-15

The chemical compositions of the stem and leaf sheath of few-flower wild rice were analysed. In addition, their extracts were evaluated for diphenylpicrylhydrazyl (DPPH) free radical-scavenging activity, ferric-reducing antioxidant power and angiotensin-converting enzyme (ACE)-inhibitory activity, since these are important properties of sources of nutraceuticals or functional foods. The stems contained more ascorbic acid (0.06 g kg(-1) fresh weight), protein (28.18 g kg(-1) dry weight (DW)), reducing sugars (308.54 g kg(-1) DW), water-soluble pectin (20.63 g kg(-1) DW), Na(2) CO(3) -soluble pectin (44.14 g kg(-1) DW), K (8 g kg(-1) dry matter (DM), S (6 g kg(-1) DM) and P (5 g kg(-1) DM) but less starch, total dietary fibre, Si, Na and Ca than the leaf sheaths. The DPPH free radical-scavenging IC(50) values of the stem and leaf sheath extracts were 19.28 and 21.22 mg mL(-1) respectively. In addition, the ACE-inhibitory IC(50) value of the stem extracts was 38.54 mg mL(-1). Both the stem and leaf sheath extracts exhibited good antioxidant properties, while good ACE-inhibitory activity was detected only in the phosphate buffer solution extracts of the stem. Few-flower wild rice could be processed into formula feeds for fish, poultry, etc. or functional foods for persons with high blood pressure. Copyright © 2011 Society of Chemical Industry.

Distribution, Source, and Ecological Risk Assessment of Polycyclic Aromatic Hydrocarbons in Surface Sediment of Liaodong Bay, Northeast China

NASA Astrophysics Data System (ADS)

Xu, Shuang; Tao, Ping; Li, Yuxia; Guo, Qi; Zhang, Yan; Wang, Man; Jia, Hongliang; Shao, Mihua

2018-01-01

Sixteen polycyclic aromatic hydrocarbons (PAHs) were determined in surface sediments from Liaodong Bay, northeast China. The concentration levels of total PAHs (Σ16PAHs) in sediment were 11.0˜249.6 ng·g-1 dry weight (dw), with a mean value of 89.9 ng·g-1 dry weight (dw). From the point of the spatial distribution, high PAHs levels were found in the western areas of Liaodong Bay. In the paper, sources of PAHs were investigated by diagnostic ratios, which indicated that pyrogenic sources were the main sources of PAHs in the sediment of Liaodong Bay. Therefore, selected PAH levels in sediments were compared with Sediments Quality Guidelines (ERM-ERL indexes) for evaluation probable toxic effects on marine organism.

MR Imaging Biomarkers to Monitor Early Response to Hypoxia-Activated Prodrug TH-302 in Pancreatic Cancer Xenografts.

PubMed

Zhang, Xiaomeng; Wojtkowiak, Jonathan W; Martinez, Gary V; Cornnell, Heather H; Hart, Charles P; Baker, Amanda F; Gillies, Robert

2016-01-01

TH-302 is a hypoxia-activated prodrug known to activate selectively under the hypoxic conditions commonly found in solid tumors. It is currently being evaluated in clinical trials, including two trials in Pancreatic Ductal Adenocarcinomas (PDAC). The current study was undertaken to evaluate imaging biomarkers for prediction and response monitoring of TH-302 efficacy in xenograft models of PDAC. Dynamic contrast-enhanced (DCE) and diffusion weighted (DW) magnetic resonance imaging (MRI) were used to monitor acute effects on tumor vasculature and cellularity, respectively. Three human PDAC xenografts with known differential responses to TH-302 were imaged prior to, and at 24 h and 48 hours following a single dose of TH-302 or vehicle to determine if imaging changes presaged changes in tumor volumes. DW-MRI was performed at five b-values to generate apparent diffusion coefficient of water (ADC) maps. For DCE-MRI, a standard clinically available contrast reagent, Gd-DTPA, was used to determine blood flow into the tumor region of interest. TH-302 induced a dramatic decrease in the DCE transfer constant (Ktrans) within 48 hours after treatment in the sensitive tumors, Hs766t and Mia PaCa-2, whereas TH-302 had no effect on the perfusion behavior of resistant SU.86.86 tumors. Tumor cellularity, estimated from ADC, was significantly increased 24 and 48 hours after treatment in Hs766t, but was not observed in the Mia PaCa-2 and SU.86.86 groups. Notably, growth inhibition of Hs766t was observed immediately (day 3) following initiation of treatment, but was not observed in MiaPaCa-2 tumors until 8 days after initiation of treatment. Based on these preclinical findings, DCE-MRI measures of vascular perfusion dynamics and ADC measures of cell density are suggested as potential TH-302 response biomarkers in clinical trials.

The accuracy of self-reported pregnancy-related weight: a systematic review.

PubMed

Headen, I; Cohen, A K; Mujahid, M; Abrams, B

2017-03-01

Self-reported maternal weight is error-prone, and the context of pregnancy may impact error distributions. This systematic review summarizes error in self-reported weight across pregnancy and assesses implications for bias in associations between pregnancy-related weight and birth outcomes. We searched PubMed and Google Scholar through November 2015 for peer-reviewed articles reporting accuracy of self-reported, pregnancy-related weight at four time points: prepregnancy, delivery, over gestation and postpartum. Included studies compared maternal self-report to anthropometric measurement or medical report of weights. Sixty-two studies met inclusion criteria. We extracted data on magnitude of error and misclassification. We assessed impact of reporting error on bias in associations between pregnancy-related weight and birth outcomes. Women underreported prepregnancy (PPW: -2.94 to -0.29 kg) and delivery weight (DW: -1.28 to 0.07 kg), and over-reported gestational weight gain (GWG: 0.33 to 3 kg). Magnitude of error was small, ranged widely, and varied by prepregnancy weight class and race/ethnicity. Misclassification was moderate (PPW: 0-48.3%; DW: 39.0-49.0%; GWG: 16.7-59.1%), and overestimated some estimates of population prevalence. However, reporting error did not largely bias associations between pregnancy-related weight and birth outcomes. Although measured weight is preferable, self-report is a cost-effective and practical measurement approach. Future researchers should develop bias correction techniques for self-reported pregnancy-related weight. © 2017 World Obesity Federation.

Histogram analysis of apparent diffusion coefficient for monitoring early response in patients with advanced cervical cancers undergoing concurrent chemo-radiotherapy.

PubMed

Meng, Jie; Zhu, Lijing; Zhu, Li; Ge, Yun; He, Jian; Zhou, Zhengyang; Yang, Xiaofeng

2017-11-01

Background Apparent diffusion coefficient (ADC) histogram analysis has been widely used in determining tumor prognosis. Purpose To investigate the dynamic changes of ADC histogram parameters during concurrent chemo-radiotherapy (CCRT) in patients with advanced cervical cancers. Material and Methods This prospective study enrolled 32 patients with advanced cervical cancers undergoing CCRT who received diffusion-weighted (DW) magnetic resonance imaging (MRI) before CCRT, at the end of the second and fourth week during CCRT and one month after CCRT completion. The ADC histogram for the entire tumor volume was generated, and a series of histogram parameters was obtained. Dynamic changes of those parameters in cervical cancers were investigated as early biomarkers for treatment response. Results All histogram parameters except AUC low showed significant changes during CCRT (all P < 0.05). There were three variable trends involving different parameters. The mode, 5th, 10th, and 25th percentiles showed similar early increase rates (33.33%, 33.99%, 34.12%, and 30.49%, respectively) at the end of the second week of CCRT. The pre-CCRT 5th and 25th percentiles of the complete response (CR) group were significantly lower than those of the partial response (PR) group. Conclusion A series of ADC histogram parameters of cervical cancers changed significantly at the early stage of CCRT, indicating their potential in monitoring early tumor response to therapy.

Natural origin arsenic in aquatic organisms from a deep oligotrophic lake under the influence of volcanic eruptions.

PubMed

Juncos, Romina; Arcagni, Marina; Rizzo, Andrea; Campbell, Linda; Arribére, María; Guevara, Sergio Ribeiro

2016-02-01

Volcanic eruptions are recognized sources of toxic elements to freshwater, including arsenic (As). In order to study the short term changes in the bioaccumulation of naturally occurring As by aquatic organisms in Lake Nahuel Huapi (Argentina), located close to the Puyehue-Cordón Caulle volcanic complex (PCCVC), we described As concentrations at different trophic levels and food web transfer patterns in three sites of the lake prior to the last PCCVC eruption (June 2011), and compared As concentrations in biota before and after the eruption. The highest As concentrations and greater variations both between sites and position in the water column, were observed in phytoplankton (3.9-64.8 µg g(-1) dry weight, DW) and small zooplankton (4.3-22.3 µg g(-1) DW). The pattern of As accumulation in aquatic organisms (whole body or muscle) was: primary producers (phytoplankton) > scrapper mollusks (9.3-15.3 µg g(-1) DW) > filter feeding mollusks (5.4-15.6 µg g(-1) DW) > omnivorous invertebrates (0.4-9.2 µg g(-1) DW) > zooplankton (1.2-3.5 µg g(-1) DW) > fish (0.2-1.9 µg g(-1) DW). We observed As biodilution in the whole food web, and in salmonids food chains, feeding on fish prey; but biomagnification in the food chain of creole perch, feeding on benthic crayfish. The impact of the 2011 PCCVC eruption on the As levels of biota was more evident in pelagic-associated organisms (zooplankton and planktivorous fish), but only in the short term, suggesting a brief high bioavailability of As in water after ash deposition. In benthic organisms As variations likely responded to shift in diet due to coverage of the littoral zone with ashes. Copyright © 2015 Elsevier Ltd. All rights reserved.

Antioxidant compounds, antioxidant activity and phenolic content in peel from three tropical fruits from Yucatan, Mexico.

PubMed

Moo-Huchin, Víctor M; Moo-Huchin, Mariela I; Estrada-León, Raciel J; Cuevas-Glory, Luis; Estrada-Mota, Iván A; Ortiz-Vázquez, Elizabeth; Betancur-Ancona, David; Sauri-Duch, Enrique

2015-01-01

The aim of this study was to determine the antioxidant compounds, antioxidant activity and content of individual phenolic compounds of freeze-dried peel from three tropical fruits grown in Yucatan, México: purple star apple (Chrysophyllum cainito L.), yellow cashew and red cashew (Anacardium occidentale). The freeze-dried peels were good source of antioxidant compounds. ABTS and DPPH values in the peel from each fruit were 3050.95-3322.31 μM Trolox/100g dry weight (DW) or 890.19-970.01 mg of vitamin C/100 g DW, and 1579.04-1680.90 μM Trolox/100 g DW or 340.18-362.18 mg of vitamin C/100 g DW, respectively. Six phenolic compounds were identified in the peel from the tropical fruits studied: ferulic, caffeic, sinapic, gallic, ellagic and myricetin. This study demonstrated that freeze-dried peels from purple star apple, yellow cashew and red cashew, could serve as potential sources of antioxidants for use in food and pharmaceutical industries. Copyright © 2014 Elsevier Ltd. All rights reserved.

Laboratory tests for the phytoextraction of heavy metals from polluted harbor sediments using aquatic plants.

PubMed

Mânzatu, Carmen; Nagy, Boldizsár; Ceccarini, Alessio; Iannelli, Renato; Giannarelli, Stefania; Majdik, Cornelia

2015-12-30

The aim of this study was to investigate the concentrations and pollution levels of heavy metals, organochlorine pesticides, and polycyclic aromatic hydrocarbons in marine sediments from the Leghorn Harbor (Italy) on the Mediterranean Sea. The phytoextraction capacity of three aquatic plants Salvinia natans, Vallisneria spiralis, and Cabomba aquatica was also tested in the removal of lead and copper, present in high concentration in these sediments. The average detectable concentrations of metals accumulated by the plants in the studied area were as follows: >3.328 ± 0.032 mg/kg dry weight (DW) of Pb and 2.641 ± 0.014 mg/kg DW of Cu for S. natans, >3.107 ± 0.034 g/kg DW for V. spiralis, and >2.400 ± 0.029 mg/kg DW for C. aquatica. The occurrence of pesticides was also analyzed in the sediment sample by gas chromatography coupled with mass spectrometry (GC/MS). Due to its metal and organic compound accumulation patterns, S. natans is a potential candidate in phytoextraction strategies. Copyright © 2015 Elsevier Ltd. All rights reserved.

The effects of the insecticide lambda-Cyhalothrin on the earthworm Eisenia fetida under experimental conditions of tropical and temperate regions.

PubMed

Garcia, Marcos; Scheffczyk, Adam; Garcia, Terezinha; Römbke, Jörg

2011-02-01

Plant Protection Products can affect soil organisms and thus might have negative impacts on soil functions. Little research has been performed on their impact on tropical soils. Therefore, the effects of the insecticide lambda-Cyhalothrin on earthworms were evaluated in acute and chronic laboratory tests modified for tropical conditions, i.e. at selected temperatures (20 and 28°C) and with two strains (temperate and tropical) of the compost worm Eisenia fetida. The insecticide was spiked in two natural soils, in OECD artificial soil and a newly developed tropical artificial soil. The effects of lambda-Cyhalothrin did rarely vary in the same soil at tropical (LC50: 68.5-229 mg a.i./kg dry weight (DW); EC50: 54.2-60.2 mg a.i./kg DW) and temperate (LC50: 99.8-140 mg a.i./kg DW; EC50: 37.4-44.5 mg a.i./kg DW) temperatures. In tests with tropical soils and high temperature, effect values differed by up to a factor of ten. Copyright © 2010 Elsevier Ltd. All rights reserved.

Occurrence of polychlorinated dibenzo-p-dioxins, dibenzofurans and biphenyls pollution in sediments from the Haihe River and Dagu Drainage River in Tianjin City, China.

PubMed

Liu, Hanxia; Zhang, Qinghua; Wang, Yawei; Cai, Zongwei; Jiang, Guibin

2007-08-01

The pollution status of polychlorinated dibenzo-p-dioxins, dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) in the sediments of Haihe River, which is the most polluted among the seven largest basins in China, Dagu Drainage River flowing through a chemical industry zone, and two other rivers flowing into Bohai Sea in Tianjin City, China were investigated. The concentrations of PCDD/Fs and PCBs in the sediments from the mainstream of Haihe River were 1.3-26pgI-TEQg(-1) dry weight (dw) and 0.07-0.54pgTEQg(-1)dw, respectively. Heavy PCDD/Fs and PCBs pollution, with 1264pgI-TEQg(-1)dw and 21pgTEQg(-1)dw, was found in sediment from Dagu Drainage River. The congener profiles of PCDD/Fs indicated that the principal contamination source was the production of pentachlorophenol (PCP) or PCP-Na in this area. The correlation between PCDD/Fs or PCBs and total organic matter (TOM) showed that PCDD/Fs or PCBs were independent on TOM.

Polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in harbor sediments from Sea Lots, Port-of-Spain, Trinidad and Tobago.

PubMed

Mohammed, Azad; Peterman, Paul; Echols, Kathy; Feltz, Kevin; Tegerdine, George; Manoo, Anton; Maraj, Dexter; Agard, John; Orazio, Carl

2011-06-01

Concentrations of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were determined in nearshore marine surficial sediments from three locations in Trinidad. Sediments were sampled at Sea Lots on the west coast, in south Port-of-Spain Harbor, south of Sea Lots at Caroni Lagoon National Park, and on Trinidad's east coast at Manzanilla. Total PCB concentrations in Sea Lots sediments ranged from 62 to 601ng/g (dry weight {dw}), which was higher than at Caroni and Manzanilla, 13 and 8ng/g dw, respectively. Total OCP concentrations at Sea Lots were ranged from 44.5 to 145ng/g dw, compared with 13.1 and 23.8n/g (dw), for Caroni and Manzanilla respectively. The concentrations of PCBs and of some OCPs in sediments from Sea Lots were above the Canadian interim sediment quality guidelines. To date, this data is the first report on the levels of PCBs and other organochlorine compounds from Trinidad and Tobago. Copyright © 2011 Elsevier Ltd. All rights reserved.

Extraction parameters and capillary electrophoresis analysis of limonin glucoside and phlorin in citrus byproducts.

PubMed

Braddock, R J; Bryan, C R

2001-12-01

Limonin glucoside (LG) and phlorin were extracted from citrus fruit tissues and assayed by capillary electrophoresis (CE). LG was determined in dried [1.20 +/- 0.10 mg of dry weight (dw)] and wet peel residues (1.16 +/- 0.04 mg of dw), orange juice finisher pulp (0.58 +/- 0.03 mg of dw), dried grapefruit seeds (2.70 +/- 0.15 mg of dw), and 50 degrees Brix molasses (2225 +/- 68 mg/L). Phlorin was purified from orange peel residue and grapefruit albedo, and concentrations were determined in some citrus products. Phlorin and LG were extracted from residues with water/pectinase or with water solutions of methanol and ethanol. Efficient LG extraction from grapefruit seeds (2.40 +/- 0.15 mg/g) was achieved with 50-65% methanol, solvent polarity P' approximately equal to 7-8. Extracts were purified and concentrated by adsorptive resins and HPLC to obtain 95% pure compounds of LG and phlorin. CE analysis did not require extract purification beyond filtration. LG and phlorin migrated as anions in electropherograms containing peaks representing other citrus flavonoids and limonoid glucosides.

Soil decontamination of 2,4,6- trinitrotoluene by alfalfa (Medicago sativa).

PubMed

Fallahi, S; Habibi-Rezaei, M; Khayami, M; Heydari, R

2007-12-15

Present study investigate the toxicity effect of 2,4,6-trinitrotoluene (TNT) on a terrestrial plant, alfalfa (Medicago sativa) in artificial soils. In this study, TNT toxicity assessment was performed on spiked silica with this nitroaromatic compound by determination of the percent of emergence and shoots and roots biomasses at the concentration range of 3.2-10000 mg kg(-1) Dry Weight (DW). The emergence was reduced by 22-32% after 5 days of exposure at TNT concentrations up to 100 mg kg(-1) DW; shoot and root biomasses were reduced by 48-50 and 63-74%, respectively after 30 days exposure at TNT concentrations < or = 32 mg kg(-1) DW. Concentrations higher than 100 mg kg(-1) DW can not be tolerated at all. Concentrations of TNT and its metabolites in silica, root and shoot were measured by High-Performance Liquid Chromatography (HPLC). Analyses of TNT spiked soil extracts reveal hat during alfalfa cultivation for 30 days, TNT was partially transformed at the extent of 15-27%. This transformation decreased at higher TNT soil concentrations. TNT is taken up and metabolized by plants to its downstream derivatives.

A new HPLC method for the detection of iodine applied to natural samples of edible seaweeds and commercial seaweed food products.

PubMed

Nitschke, Udo; Stengel, Dagmar B

2015-04-01

Rich in micronutrients and considered to contain high iodine levels, seaweeds have multiple applications as food/supplements and nutraceuticals with potential health implications. Here, we describe the development and validation of a new analytical method to quantify iodine as iodide (I(-)) using an isocratic HPLC system with UV detection; algal iodine was converted to I(-) via dry alkaline incineration. The method was successfully applied to 19 macroalgal species from three taxonomic groups and five commercially available seaweed food products. Fesh kelps contained highest levels, reaching >1.0% per dry weight (DW), but concentrations differed amongst thallus parts. In addition to kelps, other brown (Fucales: ∼ 0.05% DW) and some red species (∼ 0.05% DW) can also serve as a rich source of iodine; lowest iodine concentrations were detected in green macroalgae (∼ 0.005% DW), implying that quantities recommended for seaweed consumption may require species-specific re-evaluation to reach adequate daily intake levels. Copyright © 2014 Elsevier Ltd. All rights reserved.

Body Mass Parameters, Lipid Profiles and Protein Contents of Zebrafish Embryos and Effects of 2,4-Dinitrophenol Exposure

PubMed Central

Hachicho, Nancy; Reithel, Sarah; Miltner, Anja; Heipieper, Hermann J.; Küster, Eberhard; Luckenbach, Till

2015-01-01

Morphology and physiology of fish embryos undergo dramatic changes during their development until the onset of feeding, supplied only by endogenous yolk reserves. For obtaining an insight how these restructuring processes are reflected by body mass related parameters, dry weights (dw), contents of the elements carbon and nitrogen and lipid and protein levels were quantified in different stages within the first four days of embryo development of the zebrafish (Danio rerio). The data show age dependent changes in tissue composition. Dry weights decreased significantly from 79μgdw/egg at 0hours post fertilization (hpf) to 61 μgdw/egg after 96 hpf. The amounts of total carbon fluctuated between 460 mg g-1 and 540 mg g-1 dw, nitrogen was at about 100 mg g-1 dw and total fatty acids were between 48–73 mg g-1 dw. In contrast to these parameters that remained relatively constant, the protein content, which was 240 mg g-1 at 0 hpf, showed an overall increase of about 40%. Comparisons of intact eggs and dechorionated embryos at stages prior to hatching (24, 30, 48 hpf) showed that the differences seen for dry weight and for carbon and nitrogen contents became smaller at more advanced stages, consistent with transition of material from the chorion to embryo tissue. Further, we determined the effect of 2,4-dinitrophenol at a subacutely toxic concentration (14 μM, LC10) as a model chemical challenge on the examined body mass related parameters. The compound caused significant decreases in phospholipid and glycolipid fatty acid contents along with a decrease in the phospholipid fatty acid unsaturation index. No major changes were observed for the other examined parameters. Lipidomic studies as performed here may thus be useful for determining subacute effects of lipophilic organic compounds on lipid metabolism and on cellular membranes of zebrafish embryos. PMID:26292096

Implementation of a 5-Minute Magnetic Resonance Imaging Screening Protocol for Prostate Cancer in Men With Elevated Prostate-Specific Antigen Before Biopsy.

PubMed

Weiss, Jakob; Martirosian, Petros; Notohamiprodjo, Mike; Kaufmann, Sascha; Othman, Ahmed E; Grosse, Ulrich; Nikolaou, Konstantin; Gatidis, Sergios

2018-03-01

The aims of this study were to establish a 5-minute magnetic resonance (MR) screening protocol for prostate cancer in men before biopsy and to evaluate effects on Prostate Imaging Reporting and Data System (PI-RADS) V2 scoring in comparison to a conventional, fully diagnostic multiparametric MR imaging (mpMRI) approach. Fifty-two patients with elevated prostate-specific antigen levels and without prior biopsy were prospectively included in this institutional review board-approved study. In all patients, an mpMRI protocol according to the PI-RADS recommendations was acquired on a 3 T MRI system. In addition, an accelerated diffusion-weighted imaging sequence was acquired using simultaneous multislice technique (DW-EPISMS). Two readers independently evaluated the images for the presence/absence of prostate cancer according to the PI-RADS criteria and for additional findings. In a first reading session, only the screening protocol consisting of axial T2-weighted and DW-EPISMS images was made available. In a subsequent reading session, the mpMRI protocol was assessed blinded to the results of the first reading, serving as reference standard. Both readers successfully established a final diagnosis according to the PI-RADS criteria in the screening and mpMRI protocol. Mean lesion size was 1.2 cm in the screening and 1.4 cm in the mpMRI protocol (P = 0.4) with 35% (18/52) of PI-RADS IV/V lesions. Diagnostic performance of the screening protocol was excellent with a sensitivity and specificity of 100% for both readers with no significant differences in comparison to the mpMRI standard (P = 1.0). In 3 patients, suspicious lymph nodes were reported as additional finding, which were equally detectable in the screening and mpMRI protocol. A 5-minute MR screening protocol for prostate cancer in men with elevated prostate-specific antigen levels before biopsy is applicable for clinical routine with similar diagnostic performance as the full diagnostic mpMRI approach.

Maternal arsenic exposure, arsenic methylation efficiency, and birth outcomes in the Biomarkers of Exposure to ARsenic (BEAR) pregnancy cohort in Mexico.

PubMed

Laine, Jessica E; Bailey, Kathryn A; Rubio-Andrade, Marisela; Olshan, Andrew F; Smeester, Lisa; Drobná, Zuzana; Herring, Amy H; Stýblo, Miroslav; García-Vargas, Gonzalo G; Fry, Rebecca C

2015-02-01

Exposure to inorganic arsenic (iAs) from drinking water is a global public health problem, yet much remains unknown about the extent of exposure in susceptible populations. We aimed to establish the Biomarkers of Exposure to ARsenic (BEAR) prospective pregnancy cohort in Gómez Palacio, Mexico, to better understand the effects of iAs exposure on pregnant women and their children. Two hundred pregnant women were recruited for this study. Concentrations of iAs in drinking water (DW-iAs) and maternal urinary concentrations of iAs and its monomethylated and dimethylated metabolites (MMAs and DMAs, respectively) were determined. Birth outcomes were analyzed for their relationship to DW-iAs and to the concentrations and proportions of maternal urinary arsenicals. DW-iAs for the study subjects ranged from < 0.5 to 236 μg As/L. More than half of the women (53%) had DW-iAs that exceeded the World Health Organization's recommended guideline of 10 μg As/L. DW-iAs was significantly associated with the sum of the urinary arsenicals (U-tAs). Maternal urinary concentrations of MMAs were negatively associated with newborn birth weight and gestational age. Maternal urinary concentrations of iAs were associated with lower mean gestational age and newborn length. Biomonitoring results demonstrate that pregnant women in Gómez Palacio are exposed to potentially harmful levels of DW-iAs. The data support a relationship between iAs metabolism in pregnant women and adverse birth outcomes. The results underscore the risks associated with iAs exposure in vulnerable populations.

Atomic-scale electronic structure of the cuprate d-symmetry form factor density wave state

DOE PAGES

M. H. Hamidian; Kim, Chung Koo; Edkins, S. D.; ...

2015-10-26

Research on high-temperature superconducting cuprates is at present focused on identifying the relationship between the classic ‘pseudogap’ phenomenon 1, 2 and the more recently investigated density wave state 3–13. This state is generally characterized by a wavevector Q parallel to the planar Cu–O–Cu bonds 4–13 along with a predominantly d-symmetry form factor 14–17 (dFF-DW). To identify the microscopic mechanism giving rise to this state 18–30, one must identify the momentum-space states contributing to the dFF-DW spectral weight, determine their particle–hole phase relationship about the Fermi energy, establish whether they exhibit a characteristic energy gap, and understand the evolution of allmore » these phenomena throughout the phase diagram. Here we use energy-resolved sublattice visualization 14 of electronic structure and reveal that the characteristic energy of the dFF-DW modulations is actually the ‘pseudogap’ energy Δ 1. Moreover, we demonstrate that the dFF-DW modulations at E = –Δ 1 (filled states) occur with relative phase π compared to those at E = Δ 1 (empty states). Lastly, we show that the conventionally defined dFF-DW Q corresponds to scattering between the ‘hot frontier’ regions of momentum-space beyond which Bogoliubov quasiparticles cease to exist 30–32. These data indicate that the cuprate dFF-DW state involves particle–hole interactions focused at the pseudogap energy scale and between the four pairs of ‘hot frontier’ regions in momentum space where the pseudogap opens.« less

Proteolytic activity of selected moulds in the first fermentation of black-seeded soysauce

NASA Astrophysics Data System (ADS)

Yulifianti, R.; Ginting, E.

2018-01-01

Black-seeded soybean is preferred as normally it has higher protein content and would give black colour to the soyfiltrate for making soysauce. Mould is usually used in the first fermentation of soysauce making to prepare koji with high soluble protein as a media for the subsequent bacteria fermentation in brine solution. Black-seeded soybean of Detam 1 variety was used as the soysauce ingredient. The trial was a randomized complete design with four replicates. The treatments were (1) Rhizopus oligosporus starter (in flour form) with two day-fermentation, (2) similar R. oligosporus starter with three-day fermentation, (3) Aspergillus sojae (pure culture) with three-day fermentation and (4) A. sojae in flour form with three-day fermentation. The black-seeded soybean had 100-grain weight of 11.7 g, high protein content of 42.5% dw and fat content of 14.9% dw. Koji prepared using R. oligosporus starter with two-day fermentation had the lowest protein content (48.9% dw). Both starters of A. sojae culture and flour gave the highest soluble protein content of koji (41.0-41.5% dw), followed by R. oligosporus starter with 3 day-fermentation (35.2% dw). Whilst the lowest value was noted in koji prepared using R. oligosporus starter with two day-fermentation (30.8% dw). This suggests that both A. sojae starters had similar proteolitic activity and higher than that of R. oligosporus starter. In terms of practical application and maintenance of the mould viability by soysauce processors, the use of A. sojae flour starter with three-day fermentation is suggested.

Trace elements in lesser scaup (Aythya affinis) from the Mississippi flyway

USGS Publications Warehouse

Custer, Christine M.; Custer, T.W.; Anteau, M.J.; Afton, A.D.; Wooten, D.E.

2003-01-01

Previous research reported that concentrations of selenium in the livers of 88a??95% of lesser scaup from locations in Lake Erie, Lake St. Clair, and Lake Michigan, USA were either elevated (10a??33 A?g/g dry weight [dw]) or in the potentially harmful range (>33 A?g/g dw). In order to determine the geographic extent of these high selenium concentrations, we collected lesser scaup in Louisiana, Arkansas, Illinois, Minnesota, Wisconsin, and Manitoba and analyzed the livers for 19 trace elements. We found that all trace element concentrations, except for selenium, generally were low. Arsenic, which usually is not detected in liver samples, was detected in Louisiana and may be related to past agricultural usages. Chromium, which also is not usually detected, was only present in lesser scaup from Arkansas and may be related to fertilizer applications. Cadmium and mercury concentrations did not differ among locations and concentrations were low. Selenium concentrations in Arkansas (geometric mean=4.2 A?g/g dw) were significantly lower than those in Louisiana (10.7 A?g/g dw), Illinois (10.5 A?g/g dw), and Minnesota (8.0 A?g/gdw); concentrations in Wisconsin and Manitoba were intermediate (6.6 and 6.5 A?g/g dw). About 25% of lesser scaup livers contained elevated selenium concentrations; however, none were in the harmful range. We concluded that selenium concentrations in lesser scaup in the Mississippi Flyway are elevated in some individuals, but not to the extent that has been documented in the industrial portions of the Great Lakes.

Variation in the accumulation levels of N,N-dimethyltryptamine in micropropagated trees and in in vitro cultures of Mimosa tenuiflora.

PubMed

Nicasio, María Del Pilar; Villarreal, María Luisa; Gillet, Françoise; Bensaddek, Lamine; Fliniaux, Marc-André

2005-01-01

The present article reports the accumulation of N,N-dimethyltryptamine and its metabolic precursors (tryptophan, tryptamine) in different organs of micropropagated Mimosa tenuiflora trees (leaves, flowers and bark) subjected to seasonal variations (January and June), as well as in in vitro cultures (plantlets and calluses) of this plant species. The accumulation of all the tested compounds varied according to the organ, the month of collection, and age of the plant material. In all cases, the neurotoxic compound N,N-dimethyltryptamine (DMT) was detected with the lowest concentration 0.01% dry weight (DW) in flowers, and the highest 0.33% DW in bark. For the in vitro cultures, DMT was present in high yields in plantlets (0.1-0.2% DW), while in calluses this compound was initially detected but its concentration decreased significantly in the subsequent subcultures.

Floating plastic debris in the Central and Western Mediterranean Sea.

PubMed

Ruiz-Orejón, Luis F; Sardá, Rafael; Ramis-Pujol, Juan

2016-09-01

In two sea voyages throughout the Mediterranean (2011 and 2013) that repeated the historical travels of Archduke Ludwig Salvator of Austria (1847-1915), 71 samples of floating plastic debris were obtained with a Manta trawl. Floating plastic was observed in all the sampled sites, with an average weight concentration of 579.3 g dw km(-2) (maximum value of 9298.2 g dw km(-2)) and an average particle concentration of 147,500 items km(-2) (the maximum concentration was 1,164,403 items km(-2)). The plastic size distribution showed microplastics (<5 mm) in all the samples. The most abundant particles had a surface area of approximately 1 mm(2) (the mesh size was 333 μm). The general estimate obtained was a total value of 1455 tons dw of floating plastic in the entire Mediterranean region, with various potential spatial accumulation areas. Copyright © 2016 Elsevier Ltd. All rights reserved.

Reproductive Response of Ewes Fed with Taiwan Grass Hay (Pennisetum purpureum Schum.) Supplemented with Duckweed (Lemna sp. and Spirodela sp.)

PubMed Central

Zetina-Córdoba, P.; Ortega-Cerrilla, M. E.; Sánchez Torres-Esqueda, M. T.; Herrera-Haro, J. G.; Ortega-Jiménez, E.; Reta-Mendiola, J. L.; Vilaboa-Arroniz, J.

2012-01-01

The effect of duckweed (DW) supplementation was evaluated on dry matter intake (DMI), presence and duration of estrus, percentage of ewes repeating estrus and pregnancy rate, as well as the concentration of progesterone (P4) in multiparous crossbred ewes from Pelibuey, Dorper, and Katahdin breeds, fed with Taiwan grass hay (TWH). Eighteen ewes with 39.7±4 kg mean body weight, kept in individual pens, were randomly assigned to one of the following treatments: T1: TWH, T2: TWH plus 200 g DW, T3: TWH plus 300 g DW. The ewes were synchronized with 40 mg fluorogestone acetate (FGA) and 400 UI equine chorionic gonadotropin (eCG). Data were analyzed as a completely randomized design using the GLM procedure. DW supplementation had no effect on dry matter intake (p>0.05); however, a slight decrease of TWH intake was observed as DW supplementation increased. No differences (p>0.05) were found in the beginning of estrus, percentage of ewes presenting it, its duration, or pregnancy rate. There were no differences (p>0.05) on P4 concentration among treatments, or treatmentxperiod interaction (p>0.05). However the period was significant (p<0.01), since the P4 levels increased as time increased after the removal of the FGA device and eCG application. PMID:25049670

Free-breathing 3D diffusion MRI for high-resolution hepatic metastasis characterization in small animals.

PubMed

Ribot, Emeline J; Trotier, Aurélien J; Castets, Charles R; Dallaudière, Benjamin; Thiaudière, Eric; Franconi, Jean-Michel; Miraux, Sylvain

2016-02-01

The goal of this study was to develop a 3D diffusion weighted sequence for free breathing liver imaging in small animals at high magnetic field. Hepatic metastases were detected and the apparent diffusion coefficients (ADC) were measured. A 3D SE-EPI sequence was developed by (i) inserting a water-selective excitation radiofrequency pulse to suppress adipose tissue signal and (ii) bipolar diffusion gradients to decrease the sensitivity to respiration motion. Mice with hepatic metastases were imaged at 7T by applying b values from 200 to 1100 s/mm(2). 3D images with high spatial resolution (182 × 156 × 125 µm) were obtained in only 8 min 32 s. The modified DW-SE-EPI sequence allowed to obtain 3D abdominal images of healthy mice with fat SNR 2.5 times lower than without any fat suppression method and sharpness 2.8 times higher than on respiration-triggered images. Due to the high spatial resolution, the core and the periphery of disseminated hepatic metastases were differentiated at high b-values only, demonstrating the presence of edema and proliferating cells (with ADC of 2.65 × 10(-3) and 1.55 × 10(-3) mm(2)/s, respectively). Furthermore, these metastases were accurately distinguished from proliferating ones within the same animal at high b-values (mean ADC of 0.38 × 10(-3) mm(2)/s). Metastases of less than 1.7 mm(3) diameter were detected. The new 3D SE-EPI sequence enabled to obtain diffusion information within liver metastases. In addition of intra-metastasis heterogeneity, differences in diffusion were measured between metastases within an animal. This sequence could be used to obtain diffusion information at high magnetic field.

Variability of Target and Normal Structure Delineation Using Multimodality Imaging for Radiation Therapy of Pancreatic Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dalah, Entesar; Moraru, Ion; Paulson, Eric

Purpose: To explore the potential of multimodality imaging (dynamic contrast–enhanced magnetic resonance imaging [DCE-MRI], apparent diffusion-coefficient diffusion-weighted imaging [ADC-DWI], fluorodeoxyglucose positron emission tomography [FDG-PET], and computed tomography) to define the gross tumor volume (GTV) and organs at risk in radiation therapy planning for pancreatic cancer. Delineated volumetric changes of DCE-MRI, ADC-DWI, and FDG-PET were assessed in comparison with the finding on 3-dimensional/4-dimensional CT with and without intravenous contrast, and with pathology specimens for resectable and borderline resectable cases of pancreatic cancer. Methods and Materials: We studied a total of 19 representative patients, whose DCE-MRI, ADC-DWI, and FDG-PET data were reviewed.more » Gross tumor volume and tumor burden/active region inside pancreatic head/neck or body were delineated on MRI (denoted GTV{sub DCE}, and GTV{sub ADC}), a standardized uptake value (SUV) of 2.5, 40%SUVmax, and 50%SUVmax on FDG-PET (GTV2.5, GTV{sub 40%}, and GTV{sub 50%}). Volumes of the pancreas, duodenum, stomach, liver, and kidneys were contoured according to CT (V{sub CT}), T1-weighted MRI (V{sub T1}), and T2-weighted MRI (V{sub T2}) for 7 patients. Results: Significant statistical differences were found between the GTVs from DCE-MRI, ADC-DW, and FDG-PET, with a mean and range of 4.73 (1.00-9.79), 14.52 (3.21-25.49), 22.04 (1.00-45.69), 19.10 (4.84-45.59), and 9.80 (0.32-35.21) cm{sup 3} for GTV{sub DCE}, GTV{sub ADC}, GTV2.5, GTV{sub 40%}, and GTV{sub 50%}, respectively. The mean difference and range in the measurements of maximum dimension of tumor on DCE-MRI, ADC-DW, SUV2.5, 40%SUVmax, and 50%SUVmax compared with pathologic specimens were −0.84 (−2.24 to 0.9), 0.41 (−0.15 to 2.3), 0.58 (−1.41 to 3.69), 0.66 (−0.67 to 1.32), and 0.15 (−1.53 to 2.38) cm, respectively. The T1- and T2-based volumes for pancreas, duodenum, stomach, and liver were generally smaller compared with those from CT, except for the kidneys. Conclusions: Differences exists between DCE-, ADC-, and FDG-PET–defined target volumes for RT of pancreatic cancer. Organ at risk volumes based on MRI are generally smaller than those based on CT. Further studies combined with pathologic specimens are required to identify the optimal imaging modality or sequence to define GTV.« less

Dialysis staff encouragement and fluid control adherence in patients on hemodialysis.

PubMed

Yokoyama, Yoko; Suzukamo, Yoshimi; Hotta, Osamu; Yamazaki, Shin; Kawaguchi, Takehiko; Hasegawa, Takeshi; Chiba, Shigemi; Moriya, Toshiko; Abe, Emi; Sasaki, Satoshi; Haga, Megumi; Fukuhara, Shunichi

2009-01-01

Fluid control in patients on dialysis is an important predictor of outcome but is a difficult restriction to achieve. The authors examined the association between dialysis staff encouragement and fluid control adherence in patients on hemodialysis. This cross-sectional study used the dialysis staff encouragement subscale (DSE). The outcome measure was intradialytic weight loss (IWL) of dry weight (DW), with nonadherence defined as IWL/DW greater than 5.7%. Predictors of nonadherence were identified using logistic regression. Odds ratio (OR) was for the occurrence of nonadherence as it correlated with a one standard deviation (SD) decrease in scale score. Seventy-two patients on hemodialysis participated, 45 men (62.5%) and 27 women. The crude OR in DSE score was 1.75 (95% confidence interval [CI]: 1.02 to 3.0) and adjusted odds ratio was 2.51 (95% CI: 0.99 to 6.34). Dialysis staff encouragement is important in improving fluid control adherence.

Application of Ultrasound in a Closed System: Optimum Condition for Antioxidants Extraction of Blackberry (Rubus fructicosus) Residues.

PubMed

Zafra-Rojas, Quinatzin Y; Cruz-Cansino, Nelly S; Quintero-Lira, Aurora; Gómez-Aldapa, Carlos A; Alanís-García, Ernesto; Cervantes-Elizarrarás, Alicia; Güemes-Vera, Norma; Ramírez-Moreno, Esther

2016-07-21

Blackberry processing generates up to 20% of residues composed mainly of peel, seeds and pulp that are abundant in flavonoids. The objective of this study was to optimize the ultrasound conditions, in a closed system, for antioxidants extraction, using the response surface methodology. Blackberry (Rubus fructicosus) residues were analyzed for total phenolics, total anthocyanins, and antioxidant activity by ABTS and DPPH. The selected independent variables were ultrasound amplitude (X₁: 80%-90%) and extraction time (X₂: 10-15 min), and results were compared with conventional extraction methods. The optimal conditions for antioxidants extraction were 91% amplitude for 15 min. The results for total phenolic content and anthocyanins and antioxidant activity by ABTS and DPPH were of 1201.23 mg gallic acid equivalent (GAE)/100 g dry weight basis (dw); 379.12 mg/100 g·dw; 6318.98 µmol Trolox equivalent (TE)/100 g·dw and 9617.22 µmol TE/100 g·dw, respectively. Compared to solvent extraction methods (water and ethanol), ultrasound achieved higher extraction of all compounds except for anthocyanins. The results obtained demonstrated that ultrasound is an alternative to improve extraction yield of antioxidants from fruit residues such as blackberry.

Accuracy and variability of tumor burden measurement on multi-parametric MRI

NASA Astrophysics Data System (ADS)

Salarian, Mehrnoush; Gibson, Eli; Shahedi, Maysam; Gaed, Mena; Gómez, José A.; Moussa, Madeleine; Romagnoli, Cesare; Cool, Derek W.; Bastian-Jordan, Matthew; Chin, Joseph L.; Pautler, Stephen; Bauman, Glenn S.; Ward, Aaron D.

2014-03-01

Measurement of prostate tumour volume can inform prognosis and treatment selection, including an assessment of the suitability and feasibility of focal therapy, which can potentially spare patients the deleterious side effects of radical treatment. Prostate biopsy is the clinical standard for diagnosis but provides limited information regarding tumour volume due to sparse tissue sampling. A non-invasive means for accurate determination of tumour burden could be of clinical value and an important step toward reduction of overtreatment. Multi-parametric magnetic resonance imaging (MPMRI) is showing promise for prostate cancer diagnosis. However, the accuracy and inter-observer variability of prostate tumour volume estimation based on separate expert contouring of T2-weighted (T2W), dynamic contrastenhanced (DCE), and diffusion-weighted (DW) MRI sequences acquired using an endorectal coil at 3T is currently unknown. We investigated this question using a histologic reference standard based on a highly accurate MPMRIhistology image registration and a smooth interpolation of planimetric tumour measurements on histology. Our results showed that prostate tumour volumes estimated based on MPMRI consistently overestimated histological reference tumour volumes. The variability of tumour volume estimates across the different pulse sequences exceeded interobserver variability within any sequence. Tumour volume estimates on DCE MRI provided the lowest inter-observer variability and the highest correlation with histology tumour volumes, whereas the apparent diffusion coefficient (ADC) maps provided the lowest volume estimation error. If validated on a larger data set, the observed correlations could support the development of automated prostate tumour volume segmentation algorithms as well as correction schemes for tumour burden estimation on MPMRI.

Temporal occurrence and sources of persistent organic pollutants in suspended particulate matter from the most heavily polluted river mouth of Lake Chaohu, China.

PubMed

Liu, Cheng; Zhang, Lei; Fan, Chengxin; Xu, Fuliu; Chen, Kaining; Gu, Xiaozhi

2017-05-01

The Nanfei River is by many measures the most heavily polluted tributary to Lake Chaohu. In this study, the temporal occurrence and sources of four classes of persistent organic pollutants (POPs), including polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs), polybrominated diphenyl ethers (PBDEs), and polychlorinated biphenyls (PCBs), in suspended particulate matter (SPM) from the river mouth were investigated monthly during 2014. Results show that concentrations of all four POPs in SPM were higher than those in the sediment of Lake Chaohu. PBDEs (26.7 ng g -1 dry weight (dw)) were originated mainly from commercial deca-BDE mixtures. PCB concentrations (1.336 ng g -1 dw) were lower than those of sediments in many other water bodies worldwide. PAHs (2597 ng g -1 dw) and OCPs (57.38 ng g -1 dw) were the most common POPs. PAHs mainly had high molecular weights and originated from pyrolytic sources, with a small proportion of petrogenic origin. The predominant OCPs were DDTs, heptachlorepoxides, dieldrin, hexachlorocyclohexanes, hexachlorobenzene, and chlordanes. Most OCPs originated from historical use, except lindane. Generally, of all the POPs studied, those of primary ecological concern should be acenaphthene, fluorene, DDTs, and chlordanes. Higher concentrations of POPs were detected during winter and spring than in summer and autumn, probably because of the high river flow during the rainy season. The high concentration of POPs in the riverine SPM and the fractionation of POPs in the water and SPM of the river should be a focal point in the future study of Lake Chaohu. Copyright © 2017 Elsevier Ltd. All rights reserved.

Temperature-dependent studies on the total phenolics, flavonoids, antioxidant activities, and sugar content in six onion varieties.

PubMed

Sharma, Kavita; Ko, Eun Young; Assefa, Awraris D; Ha, Soyoung; Nile, Shivraj H; Lee, Eul Tai; Park, Se Won

2015-06-01

Heating effect on total phenol, flavonoids, antioxidant activity, and sugar content of six onion varieties has been quantitatively investigated to explore the effect of different temperatures. The onion varieties comprised one red-skinned variety, two white-skinned varieties, and three yellow-skinned varieties. The heating temperature was scanned at 80°C, 100°C, 120°C, and 150°C for 30 minutes each, and quantitative analysis was performed relative to the powdered onion at ambient temperature. Quercetin, glucosides and sugar content were analyzed using high-performance liquid chromatography. The total phenolic and antioxidant content increased in all six varieties. The total flavonoid levels showed a considerable change. On heating the onion samples at 120°C for 30 minutes, the red-skinned variety showed the highest level of total phenolic content [13712.67 ± 1034.85 μg of gallic acid equivalent/g dry weight (μg GAE/g DW)] and total flavonoids [3456.00 ± 185.82 μg of quercetin equivalents/g dry weight (μg Q/g DW)], whereas the content of total phenolics and total flavonoids were 13611.83 ± 341.61 μg GAE/g DW and 3482.87 ± 117.17 μg Q/g DW, respectively, for the yellow-skinned (Sunpower) variety. Quercetin and its glucoside contents increased up to 120°C and then decreased at 150°C, whereas the sugar content continuously decreased with heating. All cultivars showed the same pattern in the heating effect, and the predominant flavonoids were destroyed at higher temperatures. Therefore, it is improper to expose onion powder to a temperature higher than 120°C. Copyright © 2015. Published by Elsevier B.V.

Muscle mercury and selenium in fishes and semiaquatic mammals from a selenium-deficient area.

PubMed

Kalisinska, Elzbieta; Lanocha-Arendarczyk, Natalia; Kosik-Bogacka, Danuta; Budis, Halina; Pilarczyk, Bogumila; Tomza-Marciniak, Agnieszka; Podlasinska, Joanna; Cieslik, Lukasz; Popiolek, Marcin; Pirog, Agnieszka; Jedrzejewska, Ewa

2017-02-01

The aim of this study was to investigate and compare total mercury (Hg), selenium (Se), and Se:Hg molar ratios in fish muscles (phytophages n=3; benthophages n=32; predators n=5) and semiaquatic carnivores, including piscivores (the European otter n=8, the feral American mink n=7) and the omnivorous raccoon (n=37) from a riverine European ecosystem in a Se-deficient area. The Hg concentration in fish reached 0.337μg/g dry weight, dw (0.084μg/g wet weight, ww). We found significant differences among Hg levels in tested vertebrate groups (predators vs benthophages: 0.893 vs 0.281μg/g; piscivores vs omnivores: 6.085 vs 0.566μg/g dw). Fish groups did not differ in Se concentrations, with a mean value of 0.653μg/g dw. Significant differences were revealed between Se levels in piscivorous and omnivorous carnivores (0.360 vs 0.786μg/g dw, respectively). Fish Se:Hg molar ratio values were >2.2. Benthophages had higher the ratio than predators but similar to phytophages. Among carnivores, piscivores had much lower the ratio than raccoon (0.14 vs 3.75) but raccoon and fish medians did not significantly differ. We found almost two times higher Se levels in fish and raccoons compared to piscivores, possibly resulting from lower fish Se digestibility by piscivores in contrast to higher absorption of plant Se by many fish and omnivorous raccoons. Considering that a tissue Se:Hg molar ratio <1 may be connected with a Hg toxicity potential increase, we assume that piscivores in Se-deficient area are in worse situation and more exposed to Hg than fish and omnivores. Copyright © 2016 Elsevier Inc. All rights reserved.

Parameterizing the Logistic Model of Tumor Growth by DW-MRI and DCE-MRI Data to Predict Treatment Response and Changes in Breast Cancer Cellularity during Neoadjuvant Chemotherapy1

PubMed Central

Atuegwu, Nkiruka C; Arlinghaus, Lori R; Li, Xia; Chakravarthy, A Bapsi; Abramson, Vandana G; Sanders, Melinda E; Yankeelov, Thomas E

2013-01-01

Diffusion-weighted and dynamic contrast-enhanced magnetic resonance imaging (MRI) data of 28 patients were obtained pretreatment, after one cycle, and after completion of all cycles of neoadjuvant chemotherapy (NAC). For each patient at each time point, the tumor cell number was estimated using the apparent diffusion coefficient and the extravascular extracellular (ve) and plasma volume (vp) fractions. The proliferation/death rate was obtained using the number of tumor cells from the first two time points in conjunction with the logistic model of tumor growth, which was then used to predict tumor cellularity at the conclusion of NAC. The Pearson correlation coefficient between the predicted and the experimental number of tumor cells measured at the end of NAC was 0.81 (P = .0043). The proliferation rate estimated after the first cycle of therapy was able to separate patients who went on to achieve pathologic complete response from those who did not (P = .021) with a sensitivity and specificity of 82.4% and 72.7%, respectively. These data provide preliminary results indicating that incorporating readily available quantitative MRI data into a simple model of tumor growth can lead to potentially clinically relevant information for predicting an individual patient's response to NAC. PMID:23730404

Using Gambusia affinis growth and condition to assess estuarine habitat quality: A comparison of indices

USGS Publications Warehouse

Piazza, Bryan P.; La Peyre, M.K.

2010-01-01

Numerous indices have been used to estimate fish growth and condition however, differences in sensitivity and reliability of the methods have hampered efforts to identify appropriate indicators for routine evaluation of habitat quality in the field. We compared common morphometric (length, weight, somatic growth, length-weight condition) and biochemical (RNA:DNA ratio, relative DNA content, energy density) growth indices on the same wild-caught mosquitofish Gambusia affinis to examine their usefulness as indicators of habitat quality. A laboratory experiment was used to quantify growth rates of wild-caught G. affinis under different feeding treatments. Field studies consisted of both a short-term enclosure experiment (10 d) and weekly (7 wk) fish collections to compare growth indices in managed inflow and reference marshes during a winter/spring freshwater pulse event in upper Breton Sound, Louisiana, USA. Marshes flooded by restored freshwater pulses were capable of producing optimum growth (0.001 g DW d-1 DW = dry weight) and energetically valuable habitat (>6000 cal g-1 DW) for trophic transport. Because of differences in timing of response, morphometric and biochemical indices were generally not directly correlated, but there was clear agreement in direction and magnitude of response. The most striking difference in timing was that biochemical indices (RNA:DNA) responded more slowly to treatments than did morphometric growth indices. While gross patterns are comparable between indicators, differences in sensitivity and response time between indicators suggest that choice of indicator needs to be accounted for in interpretation and analysis of effects. ?? Inter-Research 2010, www.int-res.com.

The Organization of Dorsal Frontal Cortex in Humans and Macaques

PubMed Central

Mars, Rogier B.; Noonan, MaryAnn P.; Neubert, Franz-Xaver; Jbabdi, Saad; O'Reilly, Jill X.; Filippini, Nicola; Thomas, Adam G.; Rushworth, Matthew F.

2013-01-01

The human dorsal frontal cortex has been associated with the most sophisticated aspects of cognition, including those that are thought to be especially refined in humans. Here we used diffusion-weighted magnetic resonance imaging (DW-MRI) and functional MRI (fMRI) in humans and macaques to infer and compare the organization of dorsal frontal cortex in the two species. Using DW-MRI tractography-based parcellation, we identified 10 dorsal frontal regions lying between the human inferior frontal sulcus and cingulate cortex. Patterns of functional coupling between each area and the rest of the brain were then estimated with fMRI and compared with functional coupling patterns in macaques. Areas in human medial frontal cortex, including areas associated with high-level social cognitive processes such as theory of mind, showed a surprising degree of similarity in their functional coupling patterns with the frontal pole, medial prefrontal, and dorsal prefrontal convexity in the macaque. We failed to find evidence for “new” regions in human medial frontal cortex. On the lateral surface, comparison of functional coupling patterns suggested correspondences in anatomical organization distinct from those that are widely assumed. A human region sometimes referred to as lateral frontal pole more closely resembled area 46, rather than the frontal pole, of the macaque. Overall the pattern of results suggest important similarities in frontal cortex organization in humans and other primates, even in the case of regions thought to carry out uniquely human functions. The patterns of interspecies correspondences are not, however, always those that are widely assumed. PMID:23884933

Influence of parasitism on trace element contents in tissues of red fox (Vulpes vulpes) and its parasites Mesocestoides spp. (Cestoda) and Toxascaris leonina (Nematoda).

PubMed

Jankovská, Ivana; Miholová, Daniela; Bejcek, Vladimír; Vadlejch, Jaroslav; Sulc, Miloslav; Száková, Jirina; Langrová, Iva

2010-02-01

Bioaccumulation of cadmium, chromium, copper, manganese, nickel, lead, and zinc in 56 foxes (Vulpes vulpes) and their parasites Mesocestoides spp. (Cestoda) and Toxascaris leonina (Nematoda) was studied. The levels of heavy metals were determined in the livers and kidneys of the animals depending on parasitism in the following ranges: Pb, 0.029-3.556; Cd, 0.055-9.967; Cr, 0.001-0.304; Cu, 4.15-41.15; Mn, 1.81-19.94; Ni: 0.037-0.831; Zn, 52.0-212.9 microg/g dry weight (dw). Cd in parasites (0.038-3.678 microg/g dw) were comparable with those in the livers of the host and lower than in the kidneys (0.095-6.032 microg/g dw). Contents of Pb, Cr, Cu, Mn, Ni, and Zn in cestodes were predominantly higher than those in the kidney and liver of the host. Median lead levels in Mesocestoides spp. (45.6 microg/g dw) were 52-fold higher than in the kidney and liver of the red fox (Vulpes vulpes) infected by both parasites and median Pb values in T. leonina (8.98 microg/g dw) were 8-fold higher than in the tissues of the parasitized red fox. Bioaccumulation factors of copper, zinc, nickel, and manganese are lower than those of lead and mostly range from 1.9 to 24 for Mesocestoides spp. and from 1.5 to 6 for nematode T. leonina depending on the tissue of host and element. A significant decrease in the content of Pb was found in the kidney of animals infected by T. leonina (0.260 microg/g dw) as well as those infected by Mesocestoides spp. (0.457 microg/g dw) in comparison with the lead content (0.878 microg/g dw) in the kidneys of the nonparasitized red fox. Regardless of a bioaccumulation of copper and manganese in the parasites, a significant increase of the concentrations of Mn and Cu was observed in the host's livers infected predominantly by Mesocestoides spp.

Concentrations of persistent organic pollutants (POPs) and heavy metals in soil from San Luis Potosí, México.

PubMed

Perez-Vazquez, Francisco Javier; Flores-Ramirez, Rogelio; Ochoa-Martinez, Angeles Catalina; Orta-Garcia, Sandra Teresa; Hernandez-Castro, Berenice; Carrizalez-Yañez, Leticia; Pérez-Maldonado, Iván N

2015-01-01

The aim of this study was to assess the levels of polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), p,p'-dichlorodiphenyltrichloroethane (DDT), p,p'-dichlorodiphenyldichloroethylene (DDE), and four heavy metals (arsenic, cadmium, lead, and mercury) in soil from the city of San Luis Potosí in Mexico. In order to confirm the presence of the previously mentioned compounds, outdoor surface soil samples were collected and analyzed by gas chromatography/mass spectrometer for PBDEs, PCBs, DDT, and DDE. Meanwhile, heavy metals were quantified using the atomic absorption spectrophotometry technique. The total PBDEs levels ranged from 5.0 to 134 μg/kg dry weight (dw), with a total mean PBDEs level of 22.0 ± 32.5 μg/kg dw (geometric mean ± standard deviation). For PCBs, the total mean level in the studied soil was 21.6 ± 24.7 μg/kg dw (range,

The effect of tributyltin-oxide on earthworms, springtails, and plants in artificial and natural soils.

PubMed

Römbke, J; Jänsch, S; Junker, T; Pohl, B; Scheffczyk, A; Schallnass, H-J

2007-05-01

Chemical bioavailability in Organisation for Economic Co-operation and Development (OECD) artificial soil can contrast with bioavailability in natural soils and produce ecotoxicologic benchmarks that are not representative of species' exposure conditions in the field. Initially, reproduction and growth of earthworm and Collembolan species, and early seedling growth of a dicotyledonous plant species, in nine natural soils (with a wide range of physicochemical properties) and in OECD soil were evaluated. Soils that supported reproduction and growth of the test species were then used to investigate the toxicity of tributyltin-oxide (TBT-O). Natural soils caused greater toxicity of TBT-O to earthworms (EC(50) values varied from 0.5 to 4.7 mg/kg soil dry weight [dw]) compared with toxicity in OECD soil (EC(50) = 13.4 mg/kg dw). Collembolans were less sensitive to TBT-O than earthworms in natural soils, with EC(50) values ranging from 23.4 to 177.8 mg/kg dw. In contrast, the toxicity of TBT-O to collembolans in OECD soil (EC(50) = 104.0 mg/kg dw) was within the range of EC(50) values in natural soils. Phytotoxicity tests revealed even greater difference between the effects in natural soils (EC(50) values ranged from 10.7 to 189.2 mg/kg dw) and in OECD soil (EC(50) = 535.5 mg/kg dw) compared with results of the earthworm tests. Studies also showed that EC(50) values were a more robust end point compared with EC(10) values based on comparisons of coefficients of variation. These results show that toxicity testing should include studies with natural soils in addition to OECD soil to better reflect exposure conditions in the field.

Effects of hydrocarbon contamination on a free living marine nematode community: results from microcosm experiments.

PubMed

Mahmoudi, Ezzeddine; Essid, Naceur; Beyrem, Hamouda; Hedfi, Amor; Boufahja, Fehmi; Vitiello, Pierre; Aissa, Patricia

2005-11-01

Anthropogenic inputs of crude and refined petroleum hydrocarbons into the sea require knowledge of the effects of these contaminants on the receiving assemblages of organisms. A microcosm experiment was carried out to study the influence of diesel on a free living nematode community of a Tunisian lagoon. Sediments were contaminated by diesel that ranged in concentration from 0.5 to 20 mg diesel kg(-1) dry weight (dw), and effects were examined after 90 days. Gradual changes in community structure were revealed depending on the quantity of diesel administrated. In the medium (1 mg diesel kg(-1) and 5 mg diesel kg(-1) (dw)) and high (10 mg diesel kg(-1), 15 mg diesel kg(-1) and 20 mg kg(-1) (dw)) treated microcosms, most univariate measures, including diversity and species richness, decreased significantly with increasing level of diesel contamination whereas nematode assemblage from the low treated microcosm (0.5 mg diesel kg(-1) (dw)) remained unaffected. Results from multivariate analyses of the species abundance data demonstrated that responses of nematode species to the diesel treatments were varied: Chaetonema sp. was eliminated at all doses tested and seemed to be intolerant species to diesel contamination; Pomponema sp. and Oncholaimus campylocercoïdes were significantly affected at all diesel contamination levels but they were not eliminated, these species were categorized as "diesel-sensitive"; Hypodontolaimus colesi, Daptonema trabeculosum and Daptonema fallax which significantly increased respectively at 0.5, 1 and 5 mg diesel kg(-1) (dw) concentrations and appeared to be "opportunistic" species at these doses whereas Marylynnia stekhoveni which increased at all high doses (10, 15 and 20 mg diesel kg(-1) (dw)) seemed to be a "diesel-resistant" species.

Arsenic hazards to humans, plants, and animals from gold mining.

PubMed

Eisler, Ronald

2004-01-01

Arsenic sources to the biosphere associated with gold mining include waste soil and rocks, residual water from ore concentrations, roasting of some types of gold-containing ores to remove sulfur and sulfur oxides, and bacterially enhanced leaching. Arsenic concentrations near gold mining operations are elevated in abiotic materials and biota: maximum total arsenic concentrations measured were 560 microg/L in surface waters, 5.16 mg/L in sediment pore waters, 5.6 mg/kg DW in bird liver, 27 mg/kg DW in terrestrial grasses, 50 mg/kg DW in soils, 79 mg/kg DW in aquatic plants, 103 mg/kg DW in bird diets, 225 mg/kg DW in soft parts of bivalve molluscs, 324 mg/L in mine drainage waters, 625 mg/kg DW in aquatic insects, 7,700 mg/kg DW in sediments, and 21,000 mg/ kg DW in tailings. Single oral doses of arsenicals that were fatal to 50% of tested species ranged from 17 to 48 mg/kg BW in birds and from 2.5 to 33 mg/kg BW in mammals. Susceptible species of mammals were adversely affected at chronic doses of 1-10 mg As/kg BW or 50 mg As/kg diet. Sensitive aquatic species were damaged at water concentrations of 19-48 microg As/L, 120 mg As/kg diet, or tissue residues (in the case of freshwater fish) > 1.3 mg/kg fresh weight. Adverse effects to crops and vegetation were recorded at 3-28 mg of water-soluble As/L (equivalent to about 25-85 mg total As/kg soil) and at atmospheric concentrations > 3.9 microg As/m3. Gold miners had a number of arsenic-associated health problems, including excess mortality from cancer of the lung, stomach, and respiratory tract. Miners and schoolchildren in the vicinity of gold mining activities had elevated urine arsenic of 25.7 microg/L (range, 2.2-106.0 microg/L). Of the total population at this location, 20% showed elevated urine arsenic concentrations associated with future adverse health effects; arsenic-contaminated drinking water is the probable causative factor of elevated arsenic in their urine. Proposed arsenic criteria to protect human health and natural resources are listed and discussed. Many of these proposed criteria do not adequately protect sensitive species.

Comparison of Absolute Apparent Diffusion Coefficient (ADC) Values in ADC Maps Generated Across Different Postprocessing Software: Reproducibility in Endometrial Carcinoma.

PubMed

Ghosh, Adarsh; Singh, Tulika; Singla, Veenu; Bagga, Rashmi; Khandelwal, Niranjan

2017-12-01

Apparent diffusion coefficient (ADC) maps are usually generated by builtin software provided by the MRI scanner vendors; however, various open-source postprocessing software packages are available for image manipulation and parametric map generation. The purpose of this study is to establish the reproducibility of absolute ADC values obtained using different postprocessing software programs. DW images with three b values were obtained with a 1.5-T MRI scanner, and the trace images were obtained. ADC maps were automatically generated by the in-line software provided by the vendor during image generation and were also separately generated on postprocessing software. These ADC maps were compared on the basis of ROIs using paired t test, Bland-Altman plot, mountain plot, and Passing-Bablok regression plot. There was a statistically significant difference in the mean ADC values obtained from the different postprocessing software programs when the same baseline trace DW images were used for the ADC map generation. For using ADC values as a quantitative cutoff for histologic characterization of tissues, standardization of the postprocessing algorithm is essential across processing software packages, especially in view of the implementation of vendor-neutral archiving.

The disease burden of childhood adversities in adults: a population-based study.

PubMed

Cuijpers, Pim; Smit, Filip; Unger, Froukje; Stikkelbroek, Yvonne; Ten Have, Margreet; de Graaf, Ron

2011-11-01

There is much evidence showing that childhood adversities have considerable effects on the mental and physical health of adults. It could be assumed therefore, that the disease burden of childhood adversities is high. It has not yet been examined, however, whether this is true. We used data of a large representative sample (N=7,076) of the general population in the Netherlands. We calculated the disability weight (DW) for each respondent. The DW is a weight factor that reflects the severity of a disease or condition on a scale from 0 (perfect health) to 1 (equivalent to death). We used an algorithm based on the SF-6D to estimate DW. Because the DW indicates the proportion of a healthy life year that is reduced by the specific health state of the individual, it also possible to calculate the total number of years lost due to disability (YLD) in the population. We calculated the years lived with disability (YLD) for 9 different childhood adversities (in the areas of parental psychopathology; abuse and neglect; major life events), as well as for major categories of mental disorders and general medical disorders. All 9 adversities resulted in a significantly increased DW, except death of a parent before the age of 16. Adversities in the category of abuse and neglect are associated with the highest DWs (0.057), followed by parental psychopathology (0.031) and life events during childhood (0.012). All adversities (46.4% of the population reports one or more adversity) are associated with 20.7 YLD/1,000, which is more than all mental disorders together (12.9 YLD/1,000). The category of abuse/neglect has the highest YLD/1,000 (15.8), which is also higher than all mental disorders together. Adjustment for the presence of mental and general medical disorders resulted in comparable outcomes. Childhood adversities are more important from a public health point of view than all common mental disorders together, and should be a priority for public health interventions. Copyright © 2011 Elsevier Ltd. All rights reserved.

Methyl Jasmonate and Salicylic Acid Enhanced the Production of Ursolic and Oleanolic Acid in Callus Cultures of Lepechinia Caulescens

PubMed Central

Vergara Martínez, Víctor M.; Estrada-Soto, Samuel E.; Arellano-García, José de Jesús; Rivera-Leyva, Julio C.; Castillo-España, Patricia; Flores, Angélica Flores; Cardoso-Taketa, Alexandre T.; Perea-Arango, Irene

2017-01-01

Background: The production of triterpenes from plants for pharmacological purposes varies in concentration, due to genetic and environmental factors. In vitro culture enables the control and increase of these bioactive molecules. Objective: To evaluate the effect of plant growth regulators and elicitors in the induction of calli and the production of ursolic acid (UA) and oleanolic acid (OA) in Lepechinia caulescens. Materials and Methods: Leaf explants were exposed for the induction of calli at different concentrations and combinations of 2,4-dichlorophenoxyacetic acid (2,4-D) and 6-benzylaminopurine (BAP). Methyl jasmonate (MJ) and salicylic acid were used as elicitors. High-performance liquid chromatography method was used to quantify UA and OA content in each treatment. Results: Treatment with 3.0 mg/L of 2,4-D and 0.1 mg/L of BAP produced the best results for calli induction and production of UA (1.57 mg/g dry weight [DW]) and OA (1.13 mg/g DW). Both elicitors facilitated the accumulation of triterpenes. Conclusion: The combination of auxins and cytokinins showed favorable results for the induction of calli. Variation concerning the accumulation of UA and OA was observed between treatments. MJ increased the production of triterpenes five times after 8 h of exposure, compared to control treatment. There is a greater accumulation of UA (16.58 mg/g DW) and OA (1.94 mg/g DW) in leaves of wild plants. SUMMARY Callus cultures of Lepechinia caulescens were obtained from leaf explants treated with 2,4-dichlorophenoxyacetic acid and 6-bencylaminopurineResulting cultures were elicited with methyl jasmonate (MJ) and salicylic acid to increase the production of the triterpenes, ursolic acid (UA), and oleanolic acid (OA)The cultures elicited with MJ increased the production of UA and OA five times, as compared to the control. Abbreviations used: 2,4-D: 2,4-dichlorophenoxyacetic acid, BAP: 6-benzylaminopurine, DW: Dry weight, MJ: Methyl jasmonate, OA: Oleanolic acid, PGRs: Plant growth regulators, UA: Ursolic acid, SA: Salicylic acid. PMID:29491649

Toxicity and hazard of vanadium to mallard ducks (Anas platyrhynchos) and Canada geese (Branta canadensis).

PubMed

Rattner, Barnett A; McKernan, Moira A; Eisenreich, Karen M; Link, William A; Olsen, Glenn H; Hoffman, David J; Knowles, Kathy A; McGowan, Peter C

2006-02-01

A recent Canada goose (Branta canadensis) die-off at a petroleum refinery fly ash pond in Delaware was attributed to vanadium (V) toxicity. Because of the paucity of V toxicity data for wild birds, a series of studies was undertaken using the forms of V believed to have resulted in this incident. In 7-d single oral dose trials with mallard drakes (Anas platyrhynchos), the estimated median lethal dose (LD50) for vanadium pentoxide was 113 mg/kg body weight, while the LD50 for sodium metavanadate was 75.5 mg/kg. Sodium metavanadate was found to be even more potent (LD50 = 37.2 mg/kg) in male Canada geese. The most distinctive histopathological lesion of both forms of V was lympho-granulocytic enteritis with hemorrhage into the intestinal lumen. Vanadium accumulation in liver and kidney was proportional to the administered dose, and predictive analyses based on these data suggest that V concentrations of 10 microg/g dry weight (dw) in liver and 25 microg/g dw in kidney are associated with mortality (>90% confidence that exposure is >LD50) in mallards acutely exposed to sodium metavanadate. Chronic exposure to increasing dietary concentrations of sodium metavanadate (38.5 to 2651 ppm) over 67 d resulted in V accumulation in liver and kidney (25.2 and 13.6 microg/g dw, respectively), mild intestinal hemorrhage, blood chemistry changes, and evidence of hepatic oxidative stress in mallards, although some of these responses may have been confounded by food avoidance and weight loss. Dietary exposure of mallards to 250 ppm sodium metavanadate for 4 wk resulted in modest accumulation of V in liver and kidney (<5 microg/g dw) and mild intestinal hemorrhage. Based on these data and other observations, it is unlikely that chronic low-level dietary exposure to V poses a direct lethal hazard to wildlife. However, point sources, such as the V-laden fly ash pond encountered by geese at the petroleum refinery in Delaware, may pose a significant hazard to water birds.

Toxicity and hazard of vanadium to mallard ducks (Anas platyrhynchos) and Canada geese (Branta canadensis)

USGS Publications Warehouse

Rattner, Barnett A.; McKernan, Moira A.; Eisenreich, Karen M.; Link, William A.; Olsen, Glenn H.; Hoffman, David J.; Knowles, K.A.; McGowan, Peter C.

2006-01-01

A recent Canada goose (Branta canadensis) die-off at a petroleum refinery fly ash pond in Delaware was attributed to vanadium (V) toxicity. Because of the paucity of V toxicity data for wild birds, a series of studies was undertaken using the forms of V believed to have resulted in this incident. In 7-d single oral dose trials with mallard drakes (Anas platyrhynchos), the estimated median lethal dose (LD50) for vanadium pentoxide was 113 mg/kg body weight, while the LD50 for sodium metavanadate was 75.5 mg/kg. Sodium metavanadate was found to be even more potent (LD50 = 37.2 mg/kg) in male Canada geese. The most distinctive histopathological lesion of both forms of V was lympho-granulocytic enteritis with hemorrhage into the intestinal lumen. Vanadium accumulation in liver and kidney was proportional to the administered dose, and predictive analyses based on these data suggest that V concentrations of 10 μg/g dry weight (dw) in liver and 25 μg/g dw in kidney are associated with mortality (>90% confidence that exposure is >LD50) in mallards acutely exposed to sodium metavanadate. Chronic exposure to increasing dietary concentrations of sodium metavanadate (38.5 to 2651 ppm) over 67 d resulted in V accumulation in liver and kidney (25.2 and 13.6 μg/g dw, respectively), mild intestinal hemorrhage, blood chemistry changes, and evidence of hepatic oxidative stress in mallards, although some of these responses may have been confounded by food avoidance and weight loss. Dietary exposure of mallards to 250 ppm sodium metavanadate for 4 wk resulted in modest accumulation of V in liver and kidney (<5 μg/g dw) and mild intestinal hemorrhage. Based on these data and other observations, it is unlikely that chronic low-level dietary exposure to V poses a direct lethal hazard to wildlife. However, point sources, such as the V-laden fly ash pond encountered by geese at the petroleum refinery in Delaware, may pose a significant hazard to water birds.

Selenium in edible mushrooms.

PubMed

Falandysz, Jerzy

2008-01-01

Selenium is vital to human health. This article is a compendium of virtually all the published data on total selenium concentrations, its distribution in fruitbody, bioconcentration factors, and chemical forms in wild-grown, cultivated, and selenium-enriched mushrooms worldwide. Of the 190 species reviewed (belonging to 21 families and 56 genera), most are considered edible, and a few selected data relate to inedible mushrooms. Most of edible mushroom species examined until now are selenium-poor (< 1 microg Se/g dry weight). The fruitbody of some species of wild-grown edible mushrooms is naturally rich in selenium; their occurrence data are reviewed, along with information on their suitability as a dietary source of selenium for humans, the impact of cooking and possible leaching out, the significance of traditional mushroom dishes, and the element's absorption rates and co-occurrence with some potentially problematic elements. The Goat's Foot (Albatrellus pes-caprae) with approximately 200 microg Se/g dw on average (maximum up to 370 microg/g dw) is the richest one in this element among the species surveyed. Several other representatives of the genus Albatrellus are also abundant in selenium. Of the most popular edible wild-grown mushrooms, the King Bolete (Boletus edulis) is considered abundant in selenium as well; on average, it contains approximately 20 microg Se/g dw (maximum up to 70 microg/g dw). Some species of the genus Boletus, such as B. pinicola, B. aereus, B. aestivalis, B. erythropus, and B. appendiculus, can also accumulate considerable amounts of selenium. Some other relatively rich sources of selenium include the European Pine Cone Lepidella (Amanita strobiliformis), which contains, on average, approximately 20 microg Se/g dw (up to 37 microg/g dw); the Macrolepiota spp., with an average range of approximately 5 to < 10 microg/g dw (an exception is M. rhacodes with < 10 microg/g dw); and the Lycoperdon spp., with an average of approximately 5 microg Se/g dw. For several wild-grown species of the genus Agaricus, the selenium content ( approximately 5 microg/g dw) is much greater than that from cultivated Champignon Mushroom; these include A. bisporus, A. bitorquis, A. campestris, A. cesarea, A. campestris, A. edulis, A. macrosporus, and A. silvaticus. A particularly rich source of selenium could be obtained from selenium-enriched mushrooms that are cultivated on a substrate fortified with selenium (as inorganic salt or selenized-yeast). The Se-enriched Champignon Mushroom could contain up to 30 or 110 microg Se/g dw, while the Varnished Polypore (Ganoderma lucidum) could contain up to 72 microg Se/g dw. An increasingly growing database on chemical forms of selenium of mushrooms indicates that the seleno-compounds identified in carpophore include selenocysteine, selenomethionine, Se-methylselenocysteine, selenite, and several unidentified seleno-compounds; their proportions vary widely. Some aspects of environmental selenium occurrence and human body pharmacokinetics and nutritional needs will also be briefly discussed in this review.

TU-C-12A-05: Repeatability Study of Reduced Field-Of-View Diffusion-Weighted MRI On Human Thyroid Gland

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shukla-Dave, A; Lu, Y; Hatzoglou, V

2014-06-15

Purpose: To investigate the repeatability of reduced field-of-view diffusion-weighted imaging (rFOV DWI) in quantifying apparent diffusion coefficients (ADCs) for human thyroid glands in a clinical setting. Methods: Nine healthy human volunteers were enrolled and underwent 3T MRI exams. For each volunteer, 3 longitudinal exams (2 weeks apart) with 2 repetitive sessions within each exam, including rFOV and conventional full field-of-view (fFOV) DWI scans, were performed. In the acquired DWI images, a fixed-size region of interest (ROI; diameter=8mm) was placed on thyroid glands to calculate ADC. ADC was calculated using a monoexponential function with a noise correction scheme. The repeatability ofmore » ADC was assessed by using coefficient variation (CV) across sessions or exams, which was defined to be: r = 1-CV, 0 < r < 1, where CV=STD/m, STD is the standard deviation of ADC, and m is the average of ADC across sessions or exams. An experienced radiologist assessed and scored rFOV and fFOV DW images based on image characteristics (1, nondiagnostic; 2, poor; 3, satisfactory; 4, good; and 5, excellent).Analysis of variance (ANOVA) was performed to compare ADC values, CV of ADC, repeatability of ADC across sessions and exams, and radiologic scores between rFOV and fFOV DWI techniques. Results: There was no significant difference in ADC values across sessions and exams either in rFOV or fFOV DWI. The average CVs of both rFOV and fFOV DWI were less than 13%. The repeatability of ADC measurement between rFOV and fFOV DWI was not significantly different. The overall image quality was significantly higher with rFOV DWI than with fFOV DWI. Conclusion: This study suggested that ADCs from both rFOV and fFOV DWI were repeatable, but rFOV DWI had superior imaging quality for human thyroid glands in a clinical setting.« less

The histogram analysis of diffusion-weighted intravoxel incoherent motion (IVIM) imaging for differentiating the gleason grade of prostate cancer.

PubMed

Zhang, Yu-Dong; Wang, Qing; Wu, Chen-Jiang; Wang, Xiao-Ning; Zhang, Jing; Liu, Hui; Liu, Xi-Sheng; Shi, Hai-Bin

2015-04-01

To evaluate histogram analysis of intravoxel incoherent motion (IVIM) for discriminating the Gleason grade of prostate cancer (PCa). A total of 48 patients pathologically confirmed as having clinically significant PCa (size > 0.5 cm) underwent preoperative DW-MRI (b of 0-900 s/mm(2)). Data was post-processed by monoexponential and IVIM model for quantitation of apparent diffusion coefficients (ADCs), perfusion fraction f, diffusivity D and pseudo-diffusivity D*. Histogram analysis was performed by outlining entire-tumour regions of interest (ROIs) from histological-radiological correlation. The ability of imaging indices to differentiate low-grade (LG, Gleason score (GS) ≤6) from intermediate/high-grade (HG, GS > 6) PCa was analysed by ROC regression. Eleven patients had LG tumours (18 foci) and 37 patients had HG tumours (42 foci) on pathology examination. HG tumours had significantly lower ADCs and D in terms of mean, median, 10th and 75th percentiles, combined with higher histogram kurtosis and skewness for ADCs, D and f, than LG PCa (p < 0.05). Histogram D showed relatively higher correlations (ñ = 0.641-0.668 vs. ADCs: 0.544-0.574) with ordinal GS of PCa; and its mean, median and 10th percentile performed better than ADCs did in distinguishing LG from HG PCa. It is feasible to stratify the pathological grade of PCa by IVIM with histogram metrics. D performed better in distinguishing LG from HG tumour than conventional ADCs. • GS had relatively higher correlation with tumour D than ADCs. • Difference of histogram D among two-grade tumours was statistically significant. • D yielded better individual features in demonstrating tumour grade than ADC. • D* and f failed to determine tumour grade of PCa.

Relationship between starch and lipid accumulation induced by nutrient depletion and replenishment in the microalga Parachlorella kessleri.

PubMed

Fernandes, Bruno; Teixeira, José; Dragone, Giuliano; Vicente, António A; Kawano, Shigeyuki; Bišová, Kateřina; Přibyl, Pavel; Zachleder, Vilém; Vítová, Milada

2013-09-01

Photosynthetic carbon partitioning into starch and neutral lipids, as well as the influence of nutrient depletion and replenishment on growth, pigments and storage compounds, were studied in the microalga, Parachlorella kessleri. Starch was utilized as a primary carbon and energy storage compound, but nutrient depletion drove the microalgae to channel fixed carbon into lipids as secondary storage compounds. Nutrient depletion inhibited both cellular division and growth and caused degradation of chlorophyll. Starch content decreased from an initial value of 25, to around 10% of dry weight (DW), while storage lipids increased from almost 0 to about 29% of DW. After transfer of cells into replenished mineral medium, growth, reproductive processes and chlorophyll content recovered within 2 days, while the content of both starch and lipids decreased markedly to 3 or less % of DW; this suggested that they were being used as a source of energy and carbon. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effects of oxytetracycline on the abundance and community structure of nitrogen-fixing bacteria during cattle manure composting.

PubMed

Sun, Jiajun; Qian, Xun; Gu, Jie; Wang, Xiaojuan; Gao, Hua

2016-09-01

The effects of oxytetracycline (OTC) on nitrogen-fixing bacterial communities were investigated during cattle manure composting. The abundance and community structure of nitrogen-fixing bacteria were determined by qPCR and denaturing gradient gel electrophoresis (DGGE), respectively. The matrix was spiked with OTC at four levels: no OTC, 10mg/kg dry weight (DW) OTC (L), 60mg/kg DW OTC (M), and 200mg/kg DW OTC (H). The high temperature period of composting was shorter with M and H, and the decline in temperature during the cooling stage was accelerated by OTC. OTC had a concentration-dependent inhibitory effect on the nitrogenase activity during early composting, and the nifH gene abundance declined significantly during the later composting stage. The DGGE profile and statistical analysis showed that OTC changed the nitrogen-fixing bacterial community succession and reduced the community richness and dominance. The nitrogen-fixing bacterial community structure was affected greatly by the high level of OTC. Copyright © 2016. Published by Elsevier Ltd.

Relationships between hepatic trace element concentrations, reproductive status, and body condition of female greater scaup

USGS Publications Warehouse

Badzinski, Shannon S.; Flint, Paul L.; Gorman, Kristen B.; Petrie, Scott A.

2009-01-01

We collected female greater scaup (Aythya marila) on the Yukon–Kuskokwim Delta, Alaska during two breeding seasons to determine if concentrations of 18 trace elements in livers and eggs were elevated and if hepatic concentrations correlated with body condition or affected reproductive status. Fifty-six percent, 5%, and 42% of females, respectively, had elevated hepatic cadmium (Cd: >3 μg g−1 dry weight [dw]), mercury (Hg: >3 μg g−1 dw), and selenium (Se: >10 μg g−1 dw). Somatic protein and lipid reserves were not correlated with hepatic Cd or Hg, but there was a weak negative correlation between protein and Se. Hepatic Cd, Hg, and Se were similar in females that had and had not initiated egg production. In a sample of six eggs, 33% and 100%, respectively, contained Se and Hg, but concentrations were below embryotoxicity thresholds. We conclude that trace element concentrations documented likely were not adversely impacting this study population.

Levels and distribution of brominated flame retardants in the soil of Harbin in China.

PubMed

Wang, Xu; Ren, Nanqi; Qi, Hong; Ma, Wanli; Li, Yifan

2009-01-01

This study reports the presence of brominated flame retardants in the topsoil in and around Harbin, a city in northeastern China. Samples of soil were collected from 17 locations in 2006, and the levels of 9 polybrominated diphenylethers (PBDEs 17, 28, 47, 66, 99, 100, 153, 154, and 183) ranged from 2.45 to 55.9 pg/g dry weight (dw) with a mean of 26.3 pg/g dw. These levels are very low comparing with those for some cities in Europe and USA. BDE 209 and hexabromocyclododecane were the two dominant congeners, with mean concentrations of 520 pg/g dw and 1750 pg/g dw, respectively. The concentrations of the total nine PBDE congeners clearly decreased from urban areas to background, but the compositions of individual congeners differed. Proportions of heavier congeners decreased while those of lighter congeners increased, along urban-rural-background transect, providing evidence for an urban fractionation effect. Correlation analysis indicated similar sources for PBDEs, hexabromocyclododecane, and 1,2-bis(2,4,6-tribromophenoxy)-ethane from urban areas but pentabromoethylbenzene was probably present due to long-range atmospheric transport. Principal component analysis was used to determine the characteristics of the relationships among these brominated flame retardants in the field.

Effects of nutritional factors on the growth and heterotrophic eicosapentaenoic acid production of diatom Nitzschia laevis

NASA Astrophysics Data System (ADS)

Cao, Xiaohong; Li, Songyao; Wang, Chunling; Lu, Meifang

2008-08-01

The effects of several nutritional factors on the growth and eicosapentaenoic acid (EPA) production of diatom Nitzschia laevis were studied. 4 LDM (quadrupled concentration of the nutrient salt) was the optimal concentration of nutrient salt for the growth and EPA production of N. laevis. The growth of N. laevis was inhibited when the glucose concentration was either lower than 10 gL-1 or higher than 15 gL-1. Both sodium nitrate and urea were good nitrogen sources for the growth and EPA production, while ammonium chloride seriously decreased the dry cell weight (DW) and the EPA content. Silicate seriously influenced the growth of N. laevis. The maximum DW of 2.34 gL-1 was obtained in the presence of 150 mgL-1 Na2SiO3·9H2O. The EPA content remained almost the same when the silicate concentration was lower than 150 mgL-1; however, higher silicate concentrations resulted in a steady decrease of EPA content. Low medium salinity (⩽29) did not seem to influence the DW of N. laevis, and high salinity resulted in a decrease of DW. The highest EPA content (4.08%) and yield (110 mgL-1) were observed at the salinity of 36 and 29, respectively.

National inventory of perfluoroalkyl substances in archived U.S. biosolids from the 2001 EPA National Sewage Sludge Survey

PubMed Central

Venkatesan, Arjun K.; Halden, Rolf U.

2013-01-01

Using liquid chromatography tandem mass spectrometry, we determined the first nationwide inventories of 13 perfluoroalkyl substances (PFASs) in U.S. biosolids via analysis of samples collected by the U.S. Environmental Protection Agency in the 2001 National Sewage Sludge Survey. Perfluorooctane sulfonate [PFOS; 403 ± 127 ng/g dry weight (dw)] was the most abundant PFAS detected in biosolids composites representing 32 U.S. states and the District of Columbia, followed by perfluorooctanoate [PFOA; 34 ± 22 ng/g dw] and perfluorodecanoate [PFDA; 26 ± 20 ng/g dw]. Mean concentrations in U.S. biosolids of the remaining ten PFASs ranged between 2 and 21 ng/g dw. Interestingly, concentrations of PFOS determined here in biosolids collected prior to the phase-out period (2002) were similar to levels reported in the literature for recent years. The mean load of ΣPFASs in U.S. biosolids was estimated at 2749–3450 kg/year, of which about 1375–2070 kg is applied on agricultural land and 467–587 kg goes to landfills as an alternative disposal route. This study informs the risk assessment of PFASs by furnishing national inventories of PFASs occurrence and environmental release via biosolids application on land. PMID:23562984

Differential Accumulation of Mercury and Selenium in Brown Trout Tissues of a High-Gradient Urbanized Stream in Colorado, USA.

PubMed

Herrmann, S J; Nimmo, D R; Carsella, J S; Herrmann-Hoesing, L M; Turner, J A; Gregorich, J M; Heuvel, B D Vanden; Nehring, R B; Foutz, H P

2016-02-01

Total mercury (THg) and selenium (Se) were analyzed by Inductively Coupled Plasma Mass Spectrometry in 11 internal and external tissues and stomach contents from 23 brown trout, Salmo trutta, of a 22.9-km reach of a high-gradient stream (upper Fountain Creek) in Colorado, USA, impacted by coal-fired power plants, shale deposits, and urbanization. Trout and water were sampled from four sites ranging from 2335 to 1818 m elevation. Lengths, weights, and ages of fish between pairs of the four sites were not significantly different. The dry weight (dw) to wet weight (ww) conversion factor for each tissue was calculated with egg-ovary highest at 0.379 and epaxial muscle fourth highest at 0.223. THg and Se in stomach contents indicated diet and not ambient water was the major source of Hg and Se bioaccumulated. Mean THg ww in kidney was 40.33 µg/kg, and epaxial muscle second highest at 36.76 µg/kg. None of the tissues exceeded the human critical threshold for Hg. However, all 23 trout had at least one tissue type that exceeded 0.02 mg/kg THg ww for birds, and four trout tissues exceeded 0.1 mg/kg THg ww for mammals, indicating that piscivorous mammals and birds should be monitored. Se concentrations in tissues varied depending on ww or dw listing. Mean Se dw in liver was higher than ovary at the uppermost site and the two lower sites. Liver tissue, in addition to egg-ovary, should be utilized as an indicator tissue for Se toxicity.

Mercury emission and distribution: Potential environmental risks at a small-scale gold mining operation, Phichit Province, Thailand.

PubMed

Pataranawat, Poranee; Parkpian, Preeda; Polprasert, Chongrak; Delaune, R D; Jugsujinda, A

2007-07-01

Mercury (Hg) contamination was assessed in environment near an amalgamation gold recovery operation located at a small scale mining operation (Phanom Pha) in Phichit Province, Thailand. Total mercury (THg) concentrations was determined in water, sediment, bivalves in the aquatic environment and as dry deposition or atmospheric fallout on surface soil and leaves of Neem tree (Azadirachta indica Juss. var. siamensis Valeton) near the mining operation. THg in surface soil, Neem flowers (edible part) and rice grain in surrounding terrestrial habitat and with distance from the mining area were also evaluated for possible contamination. Potential environmental risks were evaluated using the hazard quotient equation. Hg analyses conducted in the aquatic habitat showed that THg in water, sediment and bivalves (Scabies cripata Gould) ranged from 0.4 to 4 microg L(-1), 96 to 402 microg kg(-1)dry weight (dw) and 15 to 584 microg kg(-1) wet weight (ww), respectively. High concentrations of THg in water, sediment and bivalves were observed in the receiving stream near the mining operation which was located near the Khao Chet Luk Reservoir. Whereas the THg concentration in water, sediment and bivalves from monitoring stations outside the gold mining operation (upstream and downstream), were considerably lower with the values of 0.4-0.8 microg L(-1), 96-140 microg kg(-1) dw and 88-658 microg kg(-1) dw, respectively. The elevated concentration of Hg found in the sediment near the mining operation was consistent with Hg accumulation measured in bivalves. The elevated Hg levels found in living bivalves collected from highly contaminated sites suggested that the sediment bound Hg was bioavailable. THg in surface soils, brown rice grain (Jasmine rice #105) and Neem flowers of terrestrial habitats were in the range of 16 to 180 microg kg(-1) dw, 190 to 300 microg kg(-1) dw, and 622 to 2150 microg kg(-1) dw, respectively. Elevated concentrations of mercury were found in Neem flowers with the concentration greater than 600 microg kg(-1) ww, which exceeds the maximum permissible concentration reported for biota tissue (500 microg kg(-1) ww). An evaluation of air and soil pollution near the mining operations showed high concentrations of THg in dry deposit from atmospheric fallout (139 microg m(-2) d(-1)), and in surface soil (10,564 microg kg(-1) dw) at station near where open burning of gold ore extracts using the amalgamation process occurred. High or elevated concentration of THg (1172-1301 microg kg(-1) dw) in leaves of Neem tree was also measured near the mining operations. A survey of Hg in surface soil showed elevated Hg concentrations near the site which corresponded to the elevated THg concentration in dry deposition. These results suggested that atmospheric fallout is a major source of Hg to the area surrounding the mining or gold ore extraction. Results also suggest that Hg emitted into the air (estimated to be 60-150 g d(-1)) from the gold mining activities (over the past 10 years) contaminated air, the aquatic environment, surface soil and biota in the area surrounding the gold mining operation.

Fractal diffusion in high temperature polymer electrolyte fuel cell membranes

NASA Astrophysics Data System (ADS)

Hopfenmüller, Bernhard; Zorn, Reiner; Holderer, Olaf; Ivanova, Oxana; Lehnert, Werner; Lüke, Wiebke; Ehlers, Georg; Jalarvo, Niina; Schneider, Gerald J.; Monkenbusch, Michael; Richter, Dieter

2018-05-01

The performance of fuel cells depends largely on the proton diffusion in the proton conducting membrane, the core of a fuel cell. High temperature polymer electrolyte fuel cells are based on a polymer membrane swollen with phosphoric acid as the electrolyte, where proton conduction takes place. We studied the proton diffusion in such membranes with neutron scattering techniques which are especially sensitive to the proton contribution. Time of flight spectroscopy and backscattering spectroscopy have been combined to cover a broad dynamic range. In order to selectively observe the diffusion of protons potentially contributing to the ion conductivity, two samples were prepared, where in one of the samples the phosphoric acid was used with hydrogen replaced by deuterium. The scattering data from the two samples were subtracted in a suitable way after measurement. Thereby subdiffusive behavior of the proton diffusion has been observed and interpreted in terms of a model of fractal diffusion. For this purpose, a scattering function for fractal diffusion has been developed. The fractal diffusion dimension dw and the Hausdorff dimension df have been determined on the length scales covered in the neutron scattering experiments.

Motion corrected DWI with integrated T2-mapping for simultaneous estimation of ADC, T2-relaxation and perfusion in prostate cancer.

PubMed

Skorpil, M; Brynolfsson, P; Engström, M

2017-06-01

Multiparametric magnetic resonance imaging (MRI) and PI-RADS (Prostate Imaging - Reporting and Data System) has become the standard to determine a probability score for a lesion being a clinically significant prostate cancer. T2-weighted and diffusion-weighted imaging (DWI) are essential in PI-RADS, depending partly on visual assessment of signal intensity, while dynamic-contrast enhanced imaging is less important. To decrease inter-rater variability and further standardize image evaluation, complementary objective measures are in need. We here demonstrate a sequence enabling simultaneous quantification of apparent diffusion coefficient (ADC) and T2-relaxation, as well as calculation of the perfusion fraction f from low b-value intravoxel incoherent motion data. Expandable wait pulses were added to a FOCUS DW SE-EPI sequence, allowing the effective echo time to change at run time. To calculate both ADC and f, b-values 200s/mm 2 and 600s/mm 2 were chosen, and for T2-estimation 6 echo times between 64.9ms and 114.9ms were used. Three patients with prostate cancer were examined and all had significantly decreased ADC and T2-values, while f was significantly increased in 2 of 3 tumors. T2 maps obtained in phantom measurements and in a healthy volunteer were compared to T2 maps from a SE sequence with consecutive scans, showing good agreement. In addition, a motion correction procedure was implemented to reduce the effects of prostate motion, which improved T2-estimation. This sequence could potentially enable more objective tumor grading, and decrease the inter-rater variability in the PI-RADS classification. Copyright © 2017 Elsevier Inc. All rights reserved.

Calcium localization and tipburn development in lettuce leaves during early enlargement

NASA Technical Reports Server (NTRS)

Barta, D. J.; Tibbitts, T. W.

2000-01-01

Tissue concentrations of Ca, Mg, and K were determined across immature leaves of lettuce (Lactuca sativa L. 'Buttercrunch') at different stages of enlargement using electron microprobe x-ray analysis. The analysis was with a wavelength dispersive spectrometer to permit detection of low concentrations of Ca. Patterns of mineral accumulation in immature leaves that were exposed were compared to patterns of accumulation in leaves that were enclosed within a developing head. The leaves developing without enclosure were free to transpire and developed normally whereas leaves developing with enclosure were restricted in transpiration and developed an injury that was characteristic of Ca deficiency. In the exposed leaves, Ca concentrations increased from an average of 1.0 to 2.1 mg g-1 dry weight (DW) as the leaves enlarged from 5 to 30 mm in length. In the enclosed leaves, Ca concentrations decreased from 1.0 to 0.7 mg g-1 DW as the leaves enlarged from 5 to 30 mm in length. At the tips of these enclosed leaves a larger decrease was found, from 0.9 to 0.3 mg g-1 DW during enlargement. Necrotic injury first became apparent in this tip area when the concentration was approximate to 0.4 mg g-1 DW. Magnesium concentrations across the exposed leaves were similar to concentrations across the enclosed leaves, and did not change with enlargement. Magnesium concentrations averaged 3.5. mg g-1 DW in both enclosed and exposed leaves during enlargement from 5 to 30 mm. In both exposed and enclosed leaves, K concentrations increased during enlargement from 40 to approximate to 60 mg g-1 DW. Potassium concentrations were highest toward the leaf apex and upper margin where injury symptoms occurred, and this may have enhanced injury development. This research documents the critical low levels of Ca (0.2 to 0.4 mg g-1 DW) that can occur in enclosed leaves of plants and which apparently leads to the marginal apex necrosis of developing leaves seen frequently on lettuce and other crops.

Andean potato cultivars (Solanum tuberosum L.) as a source of antioxidant and mineral micronutrients.

PubMed

Andre, Christelle M; Ghislain, Marc; Bertin, Pierre; Oufir, Mouhssin; Herrera, María del Rosario; Hoffmann, Lucien; Hausman, Jean-François; Larondelle, Yvan; Evers, Danièle

2007-01-24

Potato tubers were evaluated as a source of antioxidants and minerals for the human diet. A genetically diverse sample of Solanum tuberosum L. cultivars native to the Andes of South America was obtained from a collection of nearly 1000 genotypes using microsatellite markers. This size-manageable collection of 74 landraces, representing at best the genetic diversity among potato germplasm, was analyzed for iron, zinc, calcium, total phenolic, total carotenoid, and total vitamin C contents. The hydrophilic antioxidant capacity of each genotype was also measured using the oxygen radical absorbance capacity (ORAC) assay. The iron content ranged from 29.87 to 157.96 microg g-1 of dry weight (DW), the zinc content from 12.6 to 28.83 microg g-1 of DW, and the calcium content from 271.09 to 1092.93 microg g-1 of DW. Total phenolic content varied between 1.12 and 12.37 mg of gallic acid equiv g-1 of DW, total carotenoid content between 2.83 and 36.21 microg g-1 of DW, and total vitamin C content between 217.70 and 689.47 microg g-1 of DW. The range of hydrophilic ORAC values was 28.25-250.67 micromol of Trolox equiv g-1 of DW. The hydrophilic antioxidant capacity and the total phenolic content were highly and positively correlated (r = 0.91). A strong relationship between iron and calcium contents was also found (r = 0.67). Principal component analysis on the studied nutritional contents of the core collection revealed that most potato genotypes were balanced in terms of antioxidant and mineral contents, but some of them could be distinguished by their high level in distinct micronutrients. Correlations between the micronutrient contents observed in the sample and the genetic distances assessed by microsatellites were weakly significant. However, this study demonstrated the wide variability of health-promoting micronutrient levels within the native potato germplasm as well as the significant contribution that distinct potato tubers may impart to the intake in dietary antioxidants, zinc, and iron.

Safety and performance of a novel embolic deflection device in patients undergoing transcatheter aortic valve replacement: results from the DEFLECT I study.

PubMed

Baumbach, Andreas; Mullen, Michael; Brickman, Adam M; Aggarwal, Suneil K; Pietras, Cody G; Forrest, John K; Hildick-Smith, David; Meller, Stephanie M; Gambone, Louise; den Heijer, Peter; Margolis, Pauliina; Voros, Szilard; Lansky, Alexandra J

2015-05-01

This study aimed to evaluate the safety and performance of the TriGuard™ Embolic Deflection Device (EDD), a nitinol mesh filter positioned in the aortic arch across all three major cerebral artery take-offs to deflect emboli away from the cerebral circulation, in patients undergoing transcatheter aortic valve replacement (TAVR). The prospective, multicentre DEFLECT I study (NCT01448421) enrolled 37 consecutive subjects undergoing TAVR with the TriGuard EDD. Subjects underwent clinical and cognitive follow-up to 30 days; cerebral diffusion-weighted magnetic resonance imaging (DW-MRI) was performed pre-procedure and at 4±2 days post procedure. The device performed as intended with successful cerebral coverage in 80% (28/35) of cases. The primary safety endpoint (in-hospital EDD device- or EDD procedure-related cardiovascular mortality, major stroke disability, life-threatening bleeding, distal embolisation, major vascular complications, or need for acute cardiac surgery) occurred in 8.1% of subjects (VARC-defined two life-threatening bleeds and one vascular complication). The presence of new cerebral ischaemic lesions on post-procedure DW-MRI (n=28) was similar to historical controls (82% vs. 76%, p=NS). However, an exploratory analysis found that per-patient total lesion volume was 34% lower than reported historical data (0.2 vs. 0.3 cm3), and 89% lower in patients with complete (n=17) versus incomplete (n=10) cerebral vessel coverage (0.05 vs. 0.45 cm3, p=0.016). Use of the first-generation TriGuard EDD during TAVR is safe, and device performance was successful in 80% of cases during the highest embolic-risk portions of the TAVR procedure. The potential of the TriGuard EDD to reduce total cerebral ischaemic burden merits further randomised investigation.

AxTract: Toward microstructure informed tractography.

PubMed

Girard, Gabriel; Daducci, Alessandro; Petit, Laurent; Thiran, Jean-Philippe; Whittingstall, Kevin; Deriche, Rachid; Wassermann, Demian; Descoteaux, Maxime

2017-11-01

Diffusion-weighted (DW) magnetic resonance imaging (MRI) tractography has become the tool of choice to probe the human brain's white matter in vivo. However, tractography algorithms produce a large number of erroneous streamlines (false positives), largely due to complex ambiguous tissue configurations. Moreover, the relationship between the resulting streamlines and the underlying white matter microstructure characteristics remains poorly understood. In this work, we introduce a new approach to simultaneously reconstruct white matter fascicles and characterize the apparent distribution of axon diameters within fascicles. To achieve this, our method, AxTract, takes full advantage of the recent development DW-MRI microstructure acquisition, modeling, and reconstruction techniques. This enables AxTract to separate parallel fascicles with different microstructure characteristics, hence reducing ambiguities in areas of complex tissue configuration. We report a decrease in the incidence of erroneous streamlines compared to the conventional deterministic tractography algorithms on simulated data. We also report an average increase in streamline density over 15 known fascicles of the 34 healthy subjects. Our results suggest that microstructure information improves tractography in crossing areas of the white matter. Moreover, AxTract provides additional microstructure information along the fascicle that can be studied alongside other streamline-based indices. Overall, AxTract provides the means to distinguish and follow white matter fascicles using their microstructure characteristics, bringing new insights into the white matter organization. This is a step forward in microstructure informed tractography, paving the way to a new generation of algorithms able to deal with intricate configurations of white matter fibers and providing quantitative brain connectivity analysis. Hum Brain Mapp 38:5485-5500, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

MO-DE-303-03: Session on quantitative imaging for assessment of tumor response to radiation therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bowen, S.

This session will focus on quantitative imaging for assessment of tumor response to radiation therapy. This is a technically challenging method to translate to practice in radiation therapy. In the new era of precision medicine, however, delivering the right treatment, to the right patient, and at the right time, can positively impact treatment choices and patient outcomes. Quantitative imaging provides the spatial sensitivity required by radiation therapy for precision medicine that is not available by other means. In this Joint ESTRO -AAPM Symposium, three leading-edge investigators will present specific motivations for quantitative imaging biomarkers in radiation therapy of esophageal, headmore » and neck, locally advanced non-small cell lung cancer, and hepatocellular carcinoma. Experiences with the use of dynamic contrast enhanced (DCE) MRI, diffusion- weighted (DW) MRI, PET/CT, and SPECT/CT will be presented. Issues covered will include: response prediction, dose-painting, timing between therapy and imaging, within-therapy biomarkers, confounding effects, normal tissue sparing, dose-response modeling, and association with clinical biomarkers and outcomes. Current information will be presented from investigational studies and clinical practice. Learning Objectives: Learn motivations for the use of quantitative imaging biomarkers for assessment of response to radiation therapy Review the potential areas of application in cancer therapy Examine the challenges for translation, including imaging confounds and paucity of evidence to date Compare exemplary examples of the current state of the art in DCE-MRI, DW-MRI, PET/CT and SPECT/CT imaging for assessment of response to radiation therapy Van der Heide: Research grants from the Dutch Cancer Society and the European Union (FP7) Bowen: RSNA Scholar grant.« less

In vitro bioactivity and phytochemical screening of selected spices used in Mauritian foods

PubMed Central

Tacouri, Diksa Devi; Ramful-Baboolall, Deena; Puchooa, Daneshwar

2013-01-01

Objective To investigate the in vitro antioxidant and antimicrobial activities along with phytochemical screening of organic and aqueous extracts of spices used in Mauritian foods. Methods Antioxidant activity of the crude extracts was evaluated in terms of total antioxidant capacity, total phenol content and total flavonoid content. The antimicrobial activity of the spices was determined by the agar well diffusion method against a gram positive and a gram negative bacteria. The qualitative and quantitative phytochemical screening were carried out by standard biochemical assays. Results All six spices were found to possess alkaloids, coumarins, flavonoids, saponins, steroids, tannins and phenols. Total phenolic content of the extracts varied between 177 and 1 890 mg GAE/g DW while the total flavonoid content varied between 2.8 and 37.6 mg QE/g DW. All six spices were found to possess strong antioxidant properties as well. Highest value was obtained for cinnamon [(24.930±0.198) µmol Fe2+/g DW] whilst turmeric showed the lowest antioxidant activity [(5.980±0.313) µmol Fe2+/g DW] (P<0.05). All extracts showed promising activity against Staphylococcus aureus and Escherichia coli. The size of the inhibition zones ranged between (11.20±0.23) mm to (26.10±2.09) mm (P<0.05) with turmeric and cinnamon being the most effective against Staphylococcus aureus while garlic was least effective against both E. coli and S. aureus. Conclusions The present study reveals the presence of potential antioxidant and antimicrobial properties in the extracts of the spices which could be further exploited.

Quantification of total mercury in liver and heart tissue of Harbor Seals (Phoca vitulina) from Alaska USA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marino, Kady B.; Hoover-Miller, Anne; Conlon, Suzanne

This study quantified the Hg levels in the liver (n=98) and heart (n=43) tissues of Harbor Seals (Phoca vitulina) (n=102) harvested from Prince William Sound and Kodiak Island Alaska. Mercury tissue dry weight (dw) concentrations in the liver ranged from 1.7 to 393 ppm dw, and in the heart from 0.19 to 4.99 ppm dw. Results of this study indicate liver and heart tissues' Hg ppm dw concentrations significantly increase with age. Male Harbor Seals bioaccumulated Hg in both their liver and heart tissues at a significantly faster rate than females. The liver Hg bioaccumulation rates between the harvest locationsmore » Kodiak Island and Prince William Sound were not found to be significantly different. On adsorption Hg is transported throughout the Harbor Seal's body with the partition coefficient higher for the liver than the heart. No significant differences in the bio-distribution (liver:heart Hg ppm dw ratios (n=38)) values were found with respect to either age, sex or geographic harvest location. In this study the age at which Hg liver and heart bioaccumulation levels become significantly distinct in male and female Harbor Seals were identified through a Tukey's analysis. Of notably concern to human health was a male Harbor Seal's liver tissue harvested from Kodiak Island region. Mercury accumulation in this sample tissue was determined through a Q-test to be an outlier, having far higher Hg concentrarion (liver 392 Hg ppm dw) than the general population sampled. - Highlights: Black-Right-Pointing-Pointer Mercury accumulation in the liver and heart of seals exceed food safety guidelines. Black-Right-Pointing-Pointer Accumulation rate is greater in males than females with age. Black-Right-Pointing-Pointer Liver mercury accumulation is greater than in the heart tissues. Black-Right-Pointing-Pointer Mercury determination by USA EPA Method 7473 using thermal decomposition.« less

BIO-MONITORING FOR URANIUM USING STREAM-SIDE TERRESTRIAL PLANTS AND MACROPHYTES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Caldwell, E.; Duff, M.; Hicks, T.

2012-01-12

This study evaluated the abilities of various plant species to act as bio-monitors for environmental uranium (U) contamination. Vegetation and soil samples were collected from a U processing facility. The water-way fed from facility storm and processing effluents was the focal sample site as it represented a primary U transport mechanism. Soils and sediments from areas exposed to contamination possessed U concentrations that averaged 630 mg U kg{sup -1}. Aquatic mosses proved to be exceptional accumulators of U with dry weight (dw) concentrations measuring as high as 12500 mg U kg{sup -1} (approximately 1% of the dw mass was attributablemore » to U). The macrophytes (Phragmites communis, Scripus fontinalis and Sagittaria latifolia) were also effective accumulators of U. In general, plant roots possessed higher concentrations of U than associated upper portions of plants. For terrestrial plants, the roots of Impatiens capensis had the highest observed levels of U accumulation (1030 mg kg{sup -1}), followed by the roots of Cyperus esculentus and Solidago speciosa. The concentration ratio (CR) characterized dry weight (dw) vegetative U levels relative to that in associated dw soil. The plant species that accumulated U at levels in excess of that found in the soil were: P. communis root (CR, 17.4), I. capensis root (CR, 3.1) and S. fontinalis whole plant (CR, 1.4). Seven of the highest ten CR values were found in the roots. Correlations with concentrations of other metals with U were performed, which revealed that U concentrations in the plant were strongly correlated with nickel (Ni) concentrations (correlation: 0.992; r-squared: 0.984). Uranium in plant tissue was also strongly correlated with strontium (Sr) (correlation: 0.948; r-squared: 0.899). Strontium is chemically and physically similar to calcium (Ca) and magnesium (Mg), which were also positively-correlated with U. The correlation with U and these plant nutrient minerals, including iron (Fe), suggests that active uptake mechanisms may influence plant U accumulation.« less

Gastric supply manipulation to modulate ghrelin production and enhance vascularization to the cardia: proof of the concept in a porcine model.

PubMed

Diana, Michele; Halvax, Peter; Pop, Raoul; Schlagowski, Isabel; Bour, Gaetan; Liu, Yu-Yin; Legner, Andras; Diemunsch, Pierre; Geny, Bernard; Dallemagne, Bernard; Beaujeux, Rémy; Demartines, Nicolas; Marescaux, Jacques

2015-02-01

Selective embolization of the left-gastric artery (LGA) reduces levels of ghrelin and achieves significant short-term weight loss. However, embolization of the LGA would prevent the performance of bariatric procedures because the high-risk leakage area (gastroesophageal junction [GEJ]) would be devascularized. To assess an alternative vascular approach to the modulation of ghrelin levels and generate a blood flow manipulation, consequently increasing the vascular supply to the GEJ. A total of 6 pigs underwent a laparoscopic clipping of the left gastroepiploic artery. Preoperative and postoperative CT angiographies were performed. Ghrelin levels were assessed perioperatively and then once per week for 3 weeks. Reactive oxygen species (ROS; expressed as ROS/mg of dry weight [DW]), mitochondria respiratory rate, and capillary lactates were assessed before and 1 hour after clipping (T0 and T1) and after 3 weeks of survival (T2), on seromuscular biopsies. A celiac trunk angiography was performed at 3 weeks. Mean (±standard deviation) ghrelin levels were significantly reduced 1 hour after clipping (1902 ± 307.8 pg/mL vs. 1084 ± 680.0; P = .04) and at 3 weeks (954.5 ± 473.2 pg/mL; P = .01). Mean ROS levels were statistically significantly decreased at the cardia at T2 when compared with T0 (0.018 ± 0.006 mg/DW vs. 0.02957 ± 0.0096 mg/DW; P = .01) and T1 (0.0376 ± 0.008 mg/DW; P = .007). Capillary lactates were significantly decreased after 3 weeks, and the mitochondria respiratory rate remained constant over time at the cardia and pylorus, showing significant regional differences. Manipulation of the gastric flow targeting the gastroepiploic arcade induces ghrelin reduction. An endovascular approach is currently under evaluation. © The Author(s) 2014.

Method validation and reconnaissance of pharmaceuticals, personal care products, and alkylphenols in surface waters, sediments, and mussels in an urban estuary.

PubMed

Klosterhaus, Susan L; Grace, Richard; Hamilton, M Coreen; Yee, Donald

2013-04-01

Novel methods utilizing liquid chromatography-tandem mass spectrometry and gas chromatography-mass spectrometry were validated for low-level detection of 104 pharmaceuticals and personal care products ingredients (PPCPs) and four alkylphenols (APs) in environmental samples. The methods were applied to surface water, sediment, and mussel tissue samples collected from San Francisco Bay, CA, USA, an urban estuary that receives direct discharge from over forty municipal and industrial wastewater outfalls. Among the target PPCPs, 35% were detected in at least one sample, with 31, 10, and 17 compounds detected in water, sediment, and mussels, respectively. Maximum concentrations were 92 ng/L in water (valsartan), 33 ng/g dry weight (dw) in sediments (triclocarban), and 14 ng/g wet weight (ww) in mussels (N,N-diethyl-m-toluamide). Nonylphenol was detected in water (<2-73 ng/L), sediments (22-86 ng/g dw), and mussels (<0.04-95 ng/g ww), and nonylphenol mono- and diethoxylates were detected in sediments (<1-40 ng/g dw) and mussels (<5-192 ng/g ww). The concentrations of PPCPs and APs detected in the San Francisco Bay samples were generally at least an order of magnitude below concentrations expected to elicit toxic effects in aquatic organisms. This study represents the first reconnaissance of PPCPs in mussels living in an urban estuary and provides the first field-derived bioaccumulation factors (BAFs) for select compounds in aquatic organisms. Copyright © 2013 Elsevier Ltd. All rights reserved.

Characterization of peptides from common bean protein isolates and their potential to inhibit markers of type-2 diabetes, hypertension and oxidative stress.

PubMed

Mojica, Luis; Luna-Vital, Diego A; González de Mejía, Elvira

2017-06-01

Diabetes and hypertension are diseases affecting a high proportion of the world population; the use of food-based products such as common bean peptides may contribute to reduce the risk of complications associated to chronic diseases. The aim was to produce and characterize peptides from common bean protein isolates and evaluate their potential to inhibit markers of type-2 diabetes, hypertension and oxidative stress. Mexican black and Brazilian Carioca bean isolated proteins were characterized after pepsin/pancreatin digestion. Also, four synthesized pure peptides, originally found in these beans, were evaluated. Bean protein digests and pure peptides exerted dipeptidyl peptidase-IV (DPP-IV) inhibition (IC 50 = 0.03-0.87 mg dry weight (DW) mL -1 ). Lineweaver-Burk plots and computational modeling showed competitive inhibition of DPP-IV. Angiotensin-converting enzyme (ACE) inhibition ranged from IC 50 = 0.09 to 0.99 mg DW mL -1 , and α-glucosidase inhibition ranged from 36.3 to 50.1% mg -1 DW. Carioca Perola bean digested proteins presented the highest antioxidant capacity (269.3 mmol L -1 Trolox equivalent g -1 DW) as the peptide KTYGL (P > 0.05) with the most potent DPP-IV and ACE inhibition. Peptides from common bean have antidiabetic and antihypertensive potential regardless of their antioxidant capacity. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Survey of antioxidant capacity and phenolic composition of blueberry, blackberry, and strawberry in Nanjing*

PubMed Central

Huang, Wu-yang; Zhang, Hong-cheng; Liu, Wen-xu; Li, Chun-yang

2012-01-01

Berries are a good source of natural antioxidants. In the present study, the total antioxidant capacity and phenolic composition of three berry fruits (blueberry, blackberry, and strawberry) cultivated in Nanjing were investigated. Blueberry, with a Trolox equivalent antioxidant capacity (TEAC) value of 14.98 mmol Trolox/100 g dry weight (DW), exhibited the strongest total antioxidant capacity using both the 2,2-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) and the 2,2-diphenyl-1-picrylhydrazyl (DPPH) methods. Blueberry also had the highest total phenolic content (TPC, 9.44 mg gallic acid/g DW), total flavonoid content (TFC, 36.08 mg rutin/g DW), and total anthocyanidin content (TAC, 24.38 mg catechin/g DW). A preliminary analysis using high performance liquid chromatography (HPLC) showed that the blueberry, blackberry, and strawberry samples tested contained a range of phenolic acids (including gallic acid, protocatechuic acid, p-hydroxybenzoic acid, vanillic acid, caffeic acid, p-coumaric acid, ferulic acid, ellagic acid, and cinnamic acid) and various types of flavonoids (flavone: luteolin; flavonols: rutin, myricetin, quercetrin, and quercetin; flavanols: gallocatechin, epigallocatechin, catechin, and catechin gallate; anthocyanidins: malvidin-3-galactoside, malvidin-3-glucoside, and cyanidin). In particular, the blueberries had high levels of proanthocyanidins and anthocyanidins, which might be responsible for their strong antioxidant activities. These results indicate a potential market role for berries (especially blueberries) as a functional food ingredient or nutraceutical. PMID:22302422

Forest filter effect versus cold trapping effect on the altitudinal distribution of PCBs: a case study of Mt. Gongga, eastern Tibetan Plateau.

PubMed

Liu, Xin; Li, Jun; Zheng, Qian; Bing, Haijian; Zhang, Ruijie; Wang, Yan; Luo, Chunling; Liu, Xiang; Wu, Yanhong; Pan, Suhong; Zhang, Gan

2014-12-16

Mountains are observed to preferentially accumulate persistent organic pollutants (POPs) at higher altitude due to the cold condensation effect. Forest soils characterized by high organic carbon are important for terrestrial storage of POPs. To investigate the dominant factor controlling the altitudinal distribution of POPs in mountainous areas, we measured concentrations of polychlorinated biphenyls (PCBs) in different environmental matrices (soil, moss, and air) from nine elevations on the eastern slope of Mt. Gongga, the highest mountain in Sichuan Province on the Tibetan Plateau. The concentrations of 24 measured PCBs ranged from 41 to 510 pg/g dry weight (dw) (mean: 260 pg/g dw) in the O-horizon soil, 280 to 1200 pg/g dw (mean: 740 pg/g dw) in moss, and 33 to 60 pg/m(3) (mean: 47 pg/m(3)) in air. Soil organic carbon was a key determinant explaining 75% of the variation in concentration along the altitudinal gradient. Across all of the sampling sites, the average contribution of the forest filter effect (FFE) was greater than that of the mountain cold trapping effect based on principal components analysis and multiple linear regression. Our results deviate from the thermodynamic theory involving cold condensation at high altitudes of mountain areas and highlight the importance of the FFE.

Lipophilic Fraction of Cultivated Bifurcaria bifurcata R. Ross: Detailed Composition and In Vitro Prospection of Current Challenging Bioactive Properties.

PubMed

Santos, Sónia A O; Trindade, Stephanie S; Oliveira, Catia S D; Parreira, Paula; Rosa, Daniela; Duarte, Maria F; Ferreira, Isabel; Cruz, Maria T; Rego, Andreia M; Abreu, Maria H; Rocha, Silvia M; Silvestre, Armando J D

2017-11-01

Macroalgae have been seen as an alternative source of molecules with promising bioactivities to use in the prevention and treatment of current lifestyle diseases. In this vein, the lipophilic fraction of short-term (three weeks) cultivated Bifurcaria bifurcata was characterized in detail by gas chromatography-mass spectrometry (GC-MS). B. bifurcata dichloromethane extract was composed mainly by diterpenes (1892.78 ± 133.97 mg kg -1 dry weight (DW)), followed by fatty acids, both saturated (550.35 ± 15.67 mg kg -1 DW) and unsaturated (397.06 ± 18.44 mg kg -1 DW). Considerable amounts of sterols, namely fucosterol (317.68 ± 26.11 mg kg -1 DW) were also found. In vitro tests demonstrated that the B. bifurcata lipophilic extract show antioxidant, anti-inflammatory and antibacterial activities (against both Gram-positive and Gram-negative bacteria), using low extract concentrations (in the order of µg mL -1 ). Enhancement of antibiotic activity of drug families of major clinical importance was observed by the use of B. bifurcata extract. This enhancement of antibiotic activity depends on the microbial strain and on the antibiotic. This work represents the first detailed phytochemical study of the lipophilic extract of B. bifurcata and is, therefore, an important contribution for the valorization of B. bifurcata macroalgae, with promising applications in functional foods, nutraceutical, cosmetic and biomedical fields.

Factors influencing mercury in freshwater surface sediments of northeastern North America

USGS Publications Warehouse

Kamman, N.C.; Chalmers, A.; Clair, T.A.; Major, A.; Moore, R.B.; Norton, S.A.; Shanley, J.B.

2005-01-01

We report on an inventory and analysis of sediment mercury (Hg) concentrations from 579 sites across northeastern North America. Sediment Hg concentrations ranged from the limit of detection ca. 0.01-3.7 ??g g -1 (dry weight, d.w.), and the average concentration was 0.19 ??g g-1 (d.w.) Sediment methylmercury concentrations ranged from 0.15 to 21 ng g-1 (d.w.) and the mean concentration was 3.83 ng g -1 (d.w.). Total Hg concentrations (HgT) were greatest in lakes > reservoirs > rivers, although the proportion of Hg as methylmercury showed an inverse pattern. Total Hg was weakly and positively correlated with the sediment organic matter and percent of watershed as forested land, and weakly and negatively correlated with sediment solids content, drainage area, and agricultural land. Sediment methylmercury concentrations were weakly and positively correlated to wetland area, and weakly and negatively correlated to drainage area. Methylmercury, expressed as a percentage of HgT was positively correlated to agricultural land area. For sites with co-located sediment and fish-tissue sampling results, there was no relationship between sediment Hg and fish-tissue Hg. Finally, our data indicate that at least 44% of waters across the region have sediment HgT concentrations in excess of Canadian and United States minimum sediment contaminant guidelines for the protection of aquatic biota. ?? 2005 Springer Science+Business Media, Inc.

Effects of chlortetracycline, Cu and their combination on the performance and microbial community dynamics in swine manure anaerobic digestion.

PubMed

Wang, Rui; Zhang, Junya; Liu, Jibao; Yu, Dawei; Zhong, Hui; Wang, Yawei; Chen, Meixue; Tong, Juan; Wei, Yuansong

2018-05-01

Swine manure was typical for the combined pollution of heavy metals and antibiotics. The effects of widely used veterinary antibiotic chlortetracycline (CTC), Cu and their combination on swine manure anaerobic digestion performance and microbial community have never been investigated. Thus, four 2L anaerobic digestion reactors were established including reactor A (control), B (CTC spiked by 0.5g/kg dry weight, dw), C (Cu spiked by 5g/kg dw) and D (combination of CTC, 0.5g/kg dw, and Cu, 5g/kg dw), and dynamics of bacterial and archaeal community structure was investigated using high throughput sequencing method. Results showed that addition of CTC and Cu separately could increase the total biogas production by 21.6% and 15.8%, respectively, while combination of CTC and Cu severely inhibited anaerobic digestion (by 30.3%). Furthermore, corresponding to different stages and reactors, four kinds of microbes including bacteria and archaea were described in detail, and the effects of CTC, Cu and their combination mainly occurred at hydrolysis and acidification phases. The addition of Cu alone changed the dynamics of archaeal community significantly. It was genus Methanomassiliicoccus that dominated at the active methane production for A, B and D, while it was genus Methanobrevibacter and Methanoculleus for C. Copyright © 2017. Published by Elsevier B.V.

137Caesium in samples of wild-grown Boletus edulis Bull. from Lucca province (Tuscany, Italy) and other Italian and European geographical areas.

PubMed

Betti, Laura; Palego, Lionella; Lucacchini, Antonio; Giannaccini, Gino

2017-01-01

Samples of the edible mushroom Boletus edulis Bull. were studied to assess the risk for human health related to their content of the artificial radionuclide 137 Cs. Fresh B. edulis carpophores were collected in four undeveloped microhabitats of Lucca province (Tuscany, North-Central Italy). Dried non-cultivated samples coming from this same district and 11 other Italian provinces or European countries were instead purchased fromcommercial sources. Contents of 137 Cs, reported as Bq kg ‒1 dry weight (dw), were measured by γ-spectrometry. The radionuclide concentration varied depending on the gathering site in fresh samples, with 41.8 ± 5.2 Bq kg ‒1 dw at site 1 (Tosco-Emiliani Apennine) and four-fold less, 12.8 ± 1.3 Bq kg ‒1 dw, at site 2 (Apuan Alps). Moreover, fresh or dried carpophores from Lucca province displayed among the lowest 137 Cs contents in Europe. Average 137 Cs levels in all analysed samples were substantially below the legal threshold for edible mushrooms, 600 Bq kg ‒1 dw. Conclusively, we report that 137 Cs amounts in B. edulis depend on both the distance from the Chernobyl accident and multifactorial features of collection sites. We also show that the consumption of European B. edulis does not represent a major health risk with respect to 137 Cs radio contamination.

Acoustic Studies of Ocean Surface Processes in SWAPP

DTIC Science & Technology

1992-02-05

detected with an accelerometer and tiltmeters , and corrections are made in the data analysis where appropriate. Additional sensors , which are not discussed...electronics case battery case compass depth sensor submersible floats ballast weight acoustic release Figure 1. dW CN CC) Q!) CN (w UL C e Figure 2. -r

HLA heterozygosity contributes to susceptibility to rheumatoid arthritis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wordsworth, P.; Pile, K.D.; Bell, J.I.

The authors have investigated the role of HLA-DR genotypes in 184 patients with severe rheumatoid arthritis (RA) and in 46 patients with Felty syndrome, to establish the relative contribution of the RA-associated subtypes of DR4 (Dw4, Dw14, and Dw15). There was an excess of DR4 homozygotes, particularly Dw4/Dw14 compound heterozygotes (relative risk [RR] 49). The risk associated with Dw4 depended on the other allele present-Dw4/DR1 (RR 21), Dw4/Dw4 (RR 15), and Dw4/DRX (RR 6). There was a significant risk from Dw4/Dw14 compared with Dw4/Dw4, both in those with severe RA (RR 2.9; P < .02) and in those with Feltymore » syndrome (RR 4.2; P < 0.2). In contrast, in a further 63 known DR4 homozygotes with RA, not selected for severe disease, the excess of Dw4/Dw14 was much less striking (RR 1.4; not significant), suggesting that this genotype may be particularly associated with more severe disease. They also found four cases with the rare Dw4/Dw15 genotype (expected [<=]0.5; P [<=] .02). Since the Dw4, Dw14, Dw15, and DR1 molecules have similar antigen-binding sites and since combinations of these alleles particularly predispose to severe RA, the authors suggest that synergistic mechanisms are involved. These could include an effect on T-cell repertoire selection. 32 refs., 3 tabs.« less

Concentrations of arsenic, copper, cobalt, lead and zinc in cassava (Manihot esculenta Crantz) growing on uncontaminated and contaminated soils of the Zambian Copperbelt

NASA Astrophysics Data System (ADS)

Kříbek, B.; Majer, V.; Knésl, I.; Nyambe, I.; Mihaljevič, M.; Ettler, V.; Sracek, O.

2014-11-01

The concentrations of arsenic (As), copper (Cu), cobalt (Co), lead (Pb) and zinc (Zn) in washed leaves and washed and peeled tubers of cassava (Manihot esculenta Crantz, Euphorbiaceae) growing on uncontaminated and contaminated soils of the Zambian Copperbelt mining district have been analyzed. An enrichment index (EI) was used to distinguish between contaminated and uncontaminated areas. This index is based on the average ratio of the actual and median concentration of the given contaminants (As, Co, Cu, mercury (Hg), Pb and Zn) in topsoil. The concentrations of copper in cassava leaves growing on contaminated soils reach as much as 612 mg kg-1 Cu (total dry weight [dw]). Concentrations of copper in leaves of cassava growing on uncontaminated soils are much lower (up to 252 mg kg-1 Cu dw). The concentrations of Co (up to 78 mg kg-1 dw), As (up to 8 mg kg-1 dw) and Zn (up to 231 mg kg-1 dw) in leaves of cassava growing on contaminated soils are higher compared with uncontaminated areas, while the concentrations of lead do not differ significantly. The concentrations of analyzed chemical elements in the tubers of cassava are much lower than in its leaves with the exception of As. Even in strongly contaminated areas, the concentrations of copper in the leaves and tubers of cassava do not exceed the daily maximum tolerance limit of 0.5 mg kg-1/human body weight (HBW) established by the Joint FAO/WHO Expert Committee on Food Additives (JECFA). The highest tolerable weekly ingestion of 0.025 mg kg-1/HBW for lead and the highest tolerable weekly ingestion of 0.015 mg kg-1/HBW for arsenic are exceeded predominantly in the vicinity of smelters. Therefore, the preliminary assessment of dietary exposure to metals through the consumption of uncooked cassava leaves and tubers has been identified as a moderate hazard to human health. Nevertheless, as the surfaces of leaves are strongly contaminated by metalliferous dust in the polluted areas, there is still a potential hazard of ingesting dangerous levels of copper, lead and arsenic if dishes are prepared with poorly washed foliage.

Effect of long-term zinc pollution on soil microbial community resistance to repeated contamination.

PubMed

Klimek, Beata

2012-04-01

The aim of the study was to compare the effects of stress (contamination trials) on the microorganisms in zinc-polluted soil (5,018 mg Zn kg(-1) soil dry weight) and unpolluted soil (141 mg Zn kg(-1) soil dw), measured as soil respiration rate. In the laboratory, soils were subjected to copper contamination (0, 500, 1,500 and 4,500 mg kg(-1) soil dw), and then a bactericide (oxytetracycline) combined with a fungicide (captan) along with glucose (10 mg g(-1) soil dw each) were added. There was a highly significant effect of soil type, copper treatment and oxytetracycline/captan treatment. The initial respiration rate of chronically zinc-polluted soil was higher than that of unpolluted soil, but in the copper treatment it showed a greater decline. Microorganisms in copper-treated soil were more susceptible to oxytetracycline/captan contamination. After the successive soil contamination trials the decline of soil respiration was greater in zinc-polluted soil than in unpolluted soil.

Accumulation of free and covalently bound microcystins in tissues of Lymnaea stagnalis (Gastropoda) following toxic cyanobacteria or dissolved microcystin-LR exposure.

PubMed

Lance, Emilie; Neffling, Milla-Riina; Gérard, Claudia; Meriluoto, Jussi; Bormans, Myriam

2010-03-01

Accumulation of free microcystins (MCs) in freshwater gastropods has been demonstrated but accumulation of MCs covalently bound to tissues has never been considered so far. Here, we follow the accumulation of total (free and bound) MCs in Lymnaea stagnalis exposed to i) dissolved MC-LR (33 and 100 microg L(-1)) and ii) Planktothrix agardhii suspensions producing 5 and 33 microg MC-LR equivalents L(-1) over a 5-week period, and after a 3-week depuration period. Snails exposed to dissolved MC-LR accumulated up to 0.26 microg total MCs g(-1) dry weight (DW), with no detection of bound MCs. Snails exposed to MCs producing P. agardhii accumulated up to 69.9 microg total MCs g(-1) DW, of which from 17.7 to 66.7% were bound. After depuration, up to 15.3 microg g(-1) DW of bound MCs were detected in snails previously exposed to toxic cyanobacteria, representing a potential source of MCs transfer through the food web. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

Bioremediation efficiency of the largest scale artificial Porphyra yezoensis cultivation in the open sea in China.

PubMed

Wu, Hailong; Huo, Yuanzi; Zhang, Jianheng; Liu, Yuanyuan; Zhao, Yating; He, Peimin

2015-06-15

The bioremediation efficiency of China's largest scale Porphyra yezoensis cultivation for removing dissolved nutrients and controlling harmful algae was studied in the radial sandbanks waters of Jiangsu Province in the year 2012-2013. Mean nutrient concentration values in the P. yezoensis cultivation area were significantly lower than those in the non-cultivation area, especially during the cultivation season (p<0.05). Tissue nitrogen and phosphorus contents of seaweeds were 5.99-0.80% (dry weight (DW)) and 0.16-0.19% (DW), respectively. Production of P. yezoensis was 58950.87tons DW. Based on these values, 3688.15tons of tissue nitrogen and 105.61tons of tissue phosphorus were removed by harvesting P. yezoensis. The richness index of the red tide species Skeleton emacostatum declined from 0.32 to 0.05 during the P. yezoensis cultivation season. These results indicate that large-scale cultivation of P. yezoensis can be used to efficiently alleviate eutrophication and control harmful algae blooms in open sea. Copyright © 2015 Elsevier Ltd. All rights reserved.

Congener-specific distribution and bioaccumulation of short-chain chlorinated paraffins in sediments and bivalves of the Bohai Sea, China.

PubMed

Ma, Xindong; Chen, Chen; Zhang, Haijun; Gao, Yuan; Wang, Zhen; Yao, Ziwei; Chen, Jiping; Chen, Jingwen

2014-02-15

Short-chain chlorinated paraffins (SCCPs) are a new type of persistent organic pollutants that are of great environmental concern because of their wide distribution. In this study, surface sediments and bivalve samples were collected from the coastal area of the Bohai Sea in China. Total SCCP (ΣSCCP) concentrations in surface sediments and bivalves ranged from 97.4 ng g(-1) dry weight (dw) to 1756.7 ng g(-1) dw and 476.4-3269.5 ng g(-1) dw, respectively. C10-CPs and C11-CPs were the predominant homologue groups in all sediments and bivalves. Specific congener composition analysis and correspondence analysis indicated that the local SCCP source mainly came from CP-42 and CP-52 products, and riverine input had an important function. The biota-sediment accumulation factors of ΣSCCPs for bivalves ranged from 1.08 to 1.61, and a significant correlation indicated that the SCCP congener with higher chlorination degree was more likely to be accumulated in bivalves. Copyright © 2014. Published by Elsevier Ltd.

Polycyclic aromatic hydrocarbons (PAHs) and alkylated PAHs in the coastal seawater, surface sediment and oyster from Dalian, Northeast China.

PubMed

Hong, Wen-Jun; Jia, Hongliang; Li, Yi-Fan; Sun, Yeqing; Liu, Xianjie; Wang, Luo

2016-06-01

A total of 46 polycyclic aromatic hydrocarbons (PAHs, 21 parent and 25 alkylated) were determined in seawater, surface sediment and oyster from coastal area of Dalian, North China. The concentration of Σ46PAHs in seawater, sediment, and oyster were 136-621 ng/L, 172-4700 ng/g dry weight (dw) and 60.0-129 ng/g wet weight (ww) in winter, and 65.0-1130 ng/L, 71.1-1090 ng/g dw and 72.8-216 ng/g ww in summer, respectively. High PAH levels were found in industrial area both in winter and summer. Selected PAH levels in sediments were compared with Sediments Quality Guidelines (ERM-ERL, TEL-PEL indexes) for evaluation probable toxic effects on marine organism and the results indicate that surface sediment from all sampling sites have a low to medium ecotoxicological risk. Daily intake of PAHs via oyster as seafood by humans were estimated and the results indicated that oyster intake would not pose a health risk to humans even 30 days after a oil spill accident near by. Water-sediment exchange analysis showed that, both in winter and summer, the fluxes for most high molecular weight PAHs were from seawater to sediment, while for low molecular weight PAHs, an equilibrium was reached between seawater and sediment. Copyright © 2016 Elsevier Inc. All rights reserved.

Dissipated energy and entropy production for an unconventional heat engine: the stepwise `circular cycle'

NASA Astrophysics Data System (ADS)

di Liberto, Francesco; Pastore, Raffaele; Peruggi, Fulvio

2011-05-01

When some entropy is transferred, by means of a reversible engine, from a hot heat source to a colder one, the maximum efficiency occurs, i.e. the maximum available work is obtained. Similarly, a reversible heat pumps transfer entropy from a cold heat source to a hotter one with the minimum expense of energy. In contrast, if we are faced with non-reversible devices, there is some lost work for heat engines, and some extra work for heat pumps. These quantities are both related to entropy production. The lost work, i.e. ? , is also called 'degraded energy' or 'energy unavailable to do work'. The extra work, i.e. ? , is the excess of work performed on the system in the irreversible process with respect to the reversible one (or the excess of heat given to the hotter source in the irreversible process). Both quantities are analysed in detail and are evaluated for a complex process, i.e. the stepwise circular cycle, which is similar to the stepwise Carnot cycle. The stepwise circular cycle is a cycle performed by means of N small weights, dw, which are first added and then removed from the piston of the vessel containing the gas or vice versa. The work performed by the gas can be found as the increase of the potential energy of the dw's. Each single dw is identified and its increase, i.e. its increase in potential energy, evaluated. In such a way it is found how the energy output of the cycle is distributed among the dw's. The size of the dw's affects entropy production and therefore the lost and extra work. The distribution of increases depends on the chosen removal process.

Differential mercury transfer in the aquatic food web of a double basined lake associated with selenium and habitat.

PubMed

Arcagni, Marina; Campbell, Linda; Arribére, María A; Marvin-Dipasquale, Mark; Rizzo, Andrea; Ribeiro Guevara, Sergio

2013-06-01

Food web trophodynamics of total mercury (THg) and selenium (Se) were assessed for the double-basined ultraoligotrophic system of Lake Moreno, Patagonia. Each basin has differing proportions of littoral and pelagic habitats, thereby providing an opportunity to assess the importance of habitat (e.g. food web structure or benthic MeHg production) in the transfer of Hg and Se to top trophic fish species. Pelagic plankton, analyzed in three size classes (10-53, 53-200, and >200 μm), had very high [THg], exceeding 200 μg g(-1) dry weight (DW) in the smallest, and a low ratio of MeHg to THg (0.1 to 3%). In contrast, [THg] in littoral macroinvertebrates showed lower values (0.3 to 1.8 μg g(-1) DW). Juvenile and small fish species feeding upon plankton had higher [THg] (0.2 to 8 μg g(-1) muscle DW) compared to large piscivore fish species (0.1 to 1.6 μg g(-1) muscle DW). Selenium concentrations exhibited a much narrower variation range than THg in the food web, varying from 0.5 to 2.7 μg g(-1) DW. Molar Se:Hg ratios exceeded 1 for the majority of organisms in both basins, with most ratios exceeding 10. Using stable nitrogen isotopes as indicator of trophic level, no significant correlations were found with [THg], [Se] or Se:Hg. The apparent lack of biomagnification trends was attributed to elevated [THg] in plankton in the inorganic form mostly, as well as the possibility of consistent Se supply reducing the biomagnification in the food web of the organic portion of THg. Copyright © 2013 Elsevier B.V. All rights reserved.

Reproductive success, early life stage development, and survival of westslope cutthroat trout (Oncorhynchus clarki lewisi) exposed to elevated selenium in an area of active coal mining

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barri-Lynn Rudolph; Iisak Andreller; Christopher J. Kennedy

2008-04-15

The effects of accumulated Se on the reproductive success and larval development of cutthroat trout (Oncorhynchus clarki lewisi) collected from a site of active coal mining in British Columbia were assessed. Eggs from 12 fish from an exposed site (Clode Pond) and 16 from a reference site (O'Rourke Lake) were field-collected and reared in the laboratory. Egg Se concentrations ranged from 12.3 to 16.7 and 11.8 to 140.0 {mu}g/g dry weight (dw) from fish collected at the reference and exposed sites, respectively. Other studies, including those with this species, have not shown Se to affect egg viability. However, in themore » present study, eggs with Se concentrations >86.3 {mu}g/g dw were not successfully fertilized or were nonviable at fertilization, while eggs with concentrations >46.8 and <75.4 {mu}g/g dw were fertilized (96% reached the eyed stage) but did not produce viable fry. A significant positive relationship between egg Se concentration and alevin mortality was observed. Deformities were analyzed in surviving fry which developed from eggs with Se concentrations between 11.8 and 20.6 {mu}g/g dw. No relationship between Se concentration in eggs and deformities or edema was found in this range, suggesting that the no-effect threshold for deformity is >20.6 {mu}g/g dw. The present data, in conjunction with the data from several other studies in temperate fish, suggest that current Se thresholds are conservative for cold-water fish. 25 refs., 3 figs.« less

Mercury and selenium concentrations in biofilm, macroinvertebrates, and fish collected in the Yankee Fork of the Salmon River, Idaho, USA, and their potential effects on fish health.

PubMed

Rhea, Darren T; Farag, Aïda M; Harper, David D; McConnell, Elizabeth; Brumbaugh, William G

2013-01-01

The Yankee Fork is a large tributary of the Salmon River located in central Idaho, USA, with an extensive history of placer and dredge-mining activities. Concentrations of selenium (Se) and mercury (Hg) in various aquatic trophic levels were measured in the Yankee Fork during 2001 and 2002. Various measurements of fish health were also performed. Sites included four on the mainstem of the Yankee Fork and two off-channel sites in partially reclaimed dredge pools used as rearing habitat for cultured salmonid eggs and fry. Hg concentrations in whole mountain whitefish and shorthead sculpin ranged from 0.28 to 0.56 μg/g dry weight (dw), concentrations that are generally less than those reported to have significant impacts on fish. Biofilm and invertebrates ranged from 0.05 to 0.43 μg Hg/g dw. Se concentrations measured in biota samples from the Yankee Fork were greater than many representative samples collected in the Snake and Columbia watersheds and often exceeded literature-based toxic thresholds. Biofilm and invertebrates ranged from 0.58 to 4.66 μg Se/g dw. Whole fish ranged from 3.92 to 7.10 μg Se/g dw, and gonads ranged from 6.91 to 31.84 μg Se/g dw. Whole-body Se concentrations exceeded reported toxicological thresholds at three of four sites and concentrations in liver samples were mostly greater than concentrations shown to have negative impacts on fish health. Histological examinations performed during this study noted liver abnormalities, especially in shorthead sculpin, a bottom-dwelling species.

Differential mercury transfer in the aquatic food web of a double basined lake associated with selenium and habitat

USGS Publications Warehouse

Arcagni, Marina; Campbell, Linda; Arribére, María A.; Marvin-DiPasquale, Mark; Rizzo, Andrea; Guevara, Sergio Ribeiro

2013-01-01

Food web trophodynamics of total mercury (THg) and selenium (Se) were assessed for the double-basined ultraoligotrophic system of Lake Moreno, Patagonia. Each basin has differing proportions of littoral and pelagic habitats, thereby providing an opportunity to assess the importance of habitat (e.g. food web structure or benthic MeHg production) in the transfer of Hg and Se to top trophic fish species. Pelagic plankton, analyzed in three size classes (10–53, 53–200, and > 200 μm), had very high [THg], exceeding 200 μg g− 1 dry weight (DW) in the smallest, and a low ratio of MeHg to THg (0.1 to 3%). In contrast, [THg] in littoral macroinvertebrates showed lower values (0.3 to 1.8 μg g− 1 DW). Juvenile and small fish species feeding upon plankton had higher [THg] (0.2 to 8 μg g− 1 muscle DW) compared to large piscivore fish species (0.1 to 1.6 μg g− 1 muscle DW). Selenium concentrations exhibited a much narrower variation range than THg in the food web, varying from 0.5 to 2.7 μg g− 1 DW. Molar Se:Hg ratios exceeded 1 for the majority of organisms in both basins, with most ratios exceeding 10. Using stable nitrogen isotopes as indicator of trophic level, no significant correlations were found with [THg], [Se] or Se:Hg. The apparent lack of biomagnification trends was attributed to elevated [THg] in plankton in the inorganic form mostly, as well as the possibility of consistent Se supply reducing the biomagnification in the food web of the organic portion of THg.

Antioxidant profiling of native Andean potato tubers (Solanum tuberosum L.) reveals cultivars with high levels of beta-carotene, alpha-tocopherol, chlorogenic acid, and petanin.

PubMed

Andre, Christelle M; Oufir, Mouhssin; Guignard, Cédric; Hoffmann, Lucien; Hausman, Jean-François; Evers, Danièle; Larondelle, Yvan

2007-12-26

The antioxidant profile of 23 native Andean potato cultivars has been investigated from a human nutrition perspective. The main carotenoid and tocopherol compounds were studied using high-performance liquid chromatography coupled with a diode array detector (HPLC-DAD) and a fluorescence detector, respectively, whereas polyphenols (including anthocyanins in colored tubers) were identified by means of both HPLC-mass spectrometry and HPLC-DAD. Antioxidant profiling revealed significant genotypic variations as well as cultivars of particular interest from a nutritional point of view. Concentrations of the health-promoting carotenoids, lutein and zeaxanthin, ranged from 1.12 to 17.69 microg g(-1) of dry weight (DW) and from 0 to 17.7 microg g(-1) of DW, with cultivars 704353 and 702472 showing the highest levels in lutein and zeaxanthin, respectively. Whereas beta-carotene is rarely reported in potato tubers, remarkable levels of this dietary provitamin A carotenoid were detected in 16 native varieties, ranging from 0.42 to 2.19 microg g(-1) of DW. The amounts of alpha-tocopherol found in Andean potato tubers, extending from 2.73 to 20.80 microg g(-1) of DW, were clearly above the quantities generally reported for commercial varieties. Chlorogenic acid and its isomers dominated the polyphenolic profile of each cultivar. Dark purple-fleshed tubers from the cultivar 704429 contained exceptionally high levels of total anthocyanins (16.33 mg g(-1) of DW). The main anthocyanin was identified as petanin (petunidin-3-p-coumaroyl-rutinoside-5-glucoside). The results suggest that Andean potato cultivars should be exploited in screening and breeding programs for the development of potato varieties with enhanced health and nutritional benefits.

Mercury and selenium concentrations in biofilm, macroinvertebrates, and fish collected in the Yankee Fork of the Salmon River, Idaho, USA, and their potential effects on fish health

USGS Publications Warehouse

Rhea, Darren T.; Farag, Aïda M.; Harper, David D.; McConnell, Elizabeth; Brumbaugh, William G.

2013-01-01

The Yankee Fork is a large tributary of the Salmon River located in central Idaho, USA, with an extensive history of placer and dredge-mining activities. Concentrations of selenium (Se) and mercury (Hg) in various aquatic trophic levels were measured in the Yankee Fork during 2001 and 2002. Various measurements of fish health were also performed. Sites included four on the mainstem of the Yankee Fork and two off-channel sites in partially reclaimed dredge pools used as rearing habitat for cultured salmonid eggs and fry. Hg concentrations in whole mountain whitefish and shorthead sculpin ranged from 0.28 to 0.56 μg/g dry weight (dw), concentrations that are generally less than those reported to have significant impacts on fish. Biofilm and invertebrates ranged from 0.05 to 0.43 μg Hg/g dw. Se concentrations measured in biota samples from the Yankee Fork were greater than many representative samples collected in the Snake and Columbia watersheds and often exceeded literature-based toxic thresholds. Biofilm and invertebrates ranged from 0.58 to 4.66 μg Se/g dw. Whole fish ranged from 3.92 to 7.10 μg Se/g dw, and gonads ranged from 6.91 to 31.84 μg Se/g dw. Whole-body Se concentrations exceeded reported toxicological thresholds at three of four sites and concentrations in liver samples were mostly greater than concentrations shown to have negative impacts on fish health. Histological examinations performed during this study noted liver abnormalities, especially in shorthead sculpin, a bottom-dwelling species.

Improving the realism of white matter numerical phantoms: a step towards a better understanding of the influence of structural disorders in diffusion MRI

NASA Astrophysics Data System (ADS)

Ginsburger, Kévin; Poupon, Fabrice; Beaujoin, Justine; Estournet, Delphine; Matuschke, Felix; Mangin, Jean-François; Axer, Markus; Poupon, Cyril

2018-02-01

White matter is composed of irregularly packed axons leading to a structural disorder in the extra-axonal space. Diffusion MRI experiments using oscillating gradient spin echo sequences have shown that the diffusivity transverse to axons in this extra-axonal space is dependent on the frequency of the employed sequence. In this study, we observe the same frequency-dependence using 3D simulations of the diffusion process in disordered media. We design a novel white matter numerical phantom generation algorithm which constructs biomimicking geometric configurations with few design parameters, and enables to control the level of disorder of the generated phantoms. The influence of various geometrical parameters present in white matter, such as global angular dispersion, tortuosity, presence of Ranvier nodes, beading, on the extra-cellular perpendicular diffusivity frequency dependence was investigated by simulating the diffusion process in numerical phantoms of increasing complexity and fitting the resulting simulated diffusion MR signal attenuation with an adequate analytical model designed for trapezoidal OGSE sequences. This work suggests that angular dispersion and especially beading have non-negligible effects on this extracellular diffusion metrics that may be measured using standard OGSE DW-MRI clinical protocols.

Density and fluence dependence of lithium cell damage and recovery characteristics

NASA Technical Reports Server (NTRS)

Faith, T. J.

1971-01-01

Experimental results on lithium-containing solar cells point toward the lithium donor density gradient dN sub L/dw as being the crucial parameter in the prediction of cell behavior after irradiation by electrons. Recovery measurements on a large number of oxygen-rich and oxygen-lean lithium cells have confirmed that cell recovery speed is directly proportional to the value of the lithium gradient for electron fluences. Gradient measurements have also been correlated with lithium diffusion schedules. Results have shown that long diffusion times (25 h) with a paint-on source result in large cell-to-cell variations in gradient, probably due to a loss of the lithium source with time.

Appointing silver and bronze standards for noncovalent interactions: A comparison of spin-component-scaled (SCS), explicitly correlated (F12), and specialized wavefunction approaches

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burns, Lori A.; Marshall, Michael S.; Sherrill, C. David, E-mail: sherrill@gatech.edu

2014-12-21

A systematic examination of noncovalent interactions as modeled by wavefunction theory is presented in comparison to gold-standard quality benchmarks available for 345 interaction energies of 49 bimolecular complexes. Quantum chemical techniques examined include spin-component-scaling (SCS) variations on second-order perturbation theory (MP2) [SCS, SCS(N), SCS(MI)] and coupled cluster singles and doubles (CCSD) [SCS, SCS(MI)]; also, method combinations designed to improve dispersion contacts [DW-MP2, MP2C, MP2.5, DW-CCSD(T)-F12]; where available, explicitly correlated (F12) counterparts are also considered. Dunning basis sets augmented by diffuse functions are employed for all accessible ζ-levels; truncations of the diffuse space are also considered. After examination of both accuracymore » and performance for 394 model chemistries, SCS(MI)-MP2/cc-pVQZ can be recommended for general use, having good accuracy at low cost and no ill-effects such as imbalance between hydrogen-bonding and dispersion-dominated systems or non-parallelity across dissociation curves. Moreover, when benchmarking accuracy is desirable but gold-standard computations are unaffordable, this work recommends silver-standard [DW-CCSD(T**)-F12/aug-cc-pVDZ] and bronze-standard [MP2C-F12/aug-cc-pVDZ] model chemistries, which support accuracies of 0.05 and 0.16 kcal/mol and efficiencies of 97.3 and 5.5 h for adenine·thymine, respectively. Choice comparisons of wavefunction results with the best symmetry-adapted perturbation theory [T. M. Parker, L. A. Burns, R. M. Parrish, A. G. Ryno, and C. D. Sherrill, J. Chem. Phys. 140, 094106 (2014)] and density functional theory [L. A. Burns, Á. Vázquez-Mayagoitia, B. G. Sumpter, and C. D. Sherrill, J. Chem. Phys. 134, 084107 (2011)] methods previously studied for these databases are provided for readers' guidance.« less

Petroleum hydrocarbon concentrations in eight mollusc species along Tamilnadu coast, Bay of Bengal, India.

PubMed

Veerasingam, S; Venkatachalapathy, R; Sudhakar, S; Raja, P; Rajeswari, V

2011-01-01

Eight mollusc species and sediment samples collected from three different stations along Tamilnadu coast, Bay of Bengal, India were analysed for the levels of petroleum hydrocarbons to elucidate the status of the petroleum residues in mollusc meant for human consumption. The concentrations of petroleum hydrocarbons in sediments along Tamilnadu coast varied from 5.04-25.5 microg/g dw (dry weight). High concentration of petroleum hydrocarbons in the sediment of Uppanar estuary (25.5 +/- 1.45 microg/g dw) was perhaps land and marine based anthropogenic sources of this region. The petroleum hydrocarbon residues in eight mollusc species collected from Uppanar, Vellar and Coleroon estuaries varied between 2.44-6.04 microg/g ww (wet weight). Although the concentration of petroleum hydrocarbons in sediment of the Uppanar region was markedly higher than the background, the petroleum hydrocarbon residues in mollusc collected from Uppanar estuary did not suggest bioaccumulation. The results signified that industrial growth has affected the aquatic environments and regular monitoring will help to adopt stringent pollution control measures for better management of the aquatic region.

PCNs (polychlorinated napthalenes): dietary exposure via cereal crops, distribution and screening-level risk assessment in wheat, rice, soil and air along two tributaries of the River Chenab, Pakistan.

PubMed

Mahmood, Adeel; Malik, Riffat Naseem; Li, Jun; Zhang, Gan; Jones, Kevin C

2014-05-15

There is a lack of scientific literature regarding the bioaccumulation, dietary and toxicity exposure of PCN via food crops. The current study presents the information of dietary intake, distribution pattern and screening level risk assessment of PCN in wheat, rice, soil and air along upstream feeding tributaries of the River Chenab, Punjab Province, Pakistan. A total six air and twenty eight of soil, wheat and rice samples were collected during Jan, 2013 to June, 2013 to analyze the thirty nine PCN congeners. ∑39PCN concentrations were ranged between 0.02 and 0.21 ng g(-1) dw, 0.02-1.21 ng g(-1) dw, 24.6-233 ng g(-1) dw and 1,222-5,052 pg m(-3) in wheat, rice, soil and air samples, respectively. In this study soil exhibited higher TEQ values while in case of air, wheat and rice TEQ concentrations were in accordance with the previously reported pattern from other parts of the world. Estimated daily intake (EDI) of ∑39PCN through consumption of wheat and rice was estimated as 0.21 ng kg(-1) (body weight)day(-1) and 0.03 ng kg(-1) (body weight)day(-1), respectively. This is the first report of PCN dietary intake and screening-level risk assessment by consumption of cereal crops from Pakistan. The results of dietary and toxicity exposure of PCN warrant auxiliary devotion in future, to this group of contaminant. Copyright © 2014 Elsevier B.V. All rights reserved.

Whole-lesion apparent diffusion coefficient histogram analysis: significance in T and N staging of gastric cancers.

PubMed

Liu, Song; Zhang, Yujuan; Chen, Ling; Guan, Wenxian; Guan, Yue; Ge, Yun; He, Jian; Zhou, Zhengyang

2017-10-02

Whole-lesion apparent diffusion coefficient (ADC) histogram analysis has been introduced and proved effective in assessment of multiple tumors. However, the application of whole-volume ADC histogram analysis in gastrointestinal tumors has just started and never been reported in T and N staging of gastric cancers. Eighty patients with pathologically confirmed gastric carcinomas underwent diffusion weighted (DW) magnetic resonance imaging before surgery prospectively. Whole-lesion ADC histogram analysis was performed by two radiologists independently. The differences of ADC histogram parameters among different T and N stages were compared with independent-samples Kruskal-Wallis test. Receiver operating characteristic (ROC) analysis was performed to evaluate the performance of ADC histogram parameters in differentiating particular T or N stages of gastric cancers. There were significant differences of all the ADC histogram parameters for gastric cancers at different T (except ADC min and ADC max ) and N (except ADC max ) stages. Most ADC histogram parameters differed significantly between T1 vs T3, T1 vs T4, T2 vs T4, N0 vs N1, N0 vs N3, and some parameters (ADC 5% , ADC 10% , ADC min ) differed significantly between N0 vs N2, N2 vs N3 (all P < 0.05). Most parameters except ADC max performed well in differentiating different T and N stages of gastric cancers. Especially for identifying patients with and without lymph node metastasis, the ADC 10% yielded the largest area under the ROC curve of 0.794 (95% confidence interval, 0.677-0.911). All the parameters except ADC max showed excellent inter-observer agreement with intra-class correlation coefficients higher than 0.800. Whole-volume ADC histogram parameters held great potential in differentiating different T and N stages of gastric cancers preoperatively.

Radiological indeterminate vestibular schwannoma and meningioma in cerebellopontine angle area: differentiating using whole-tumor histogram analysis of apparent diffusion coefficient.

PubMed

Xu, Xiao-Quan; Li, Yan; Hong, Xun-Ning; Wu, Fei-Yun; Shi, Hai-Bin

2017-02-01

To assess the role of whole-tumor histogram analysis of apparent diffusion coefficient (ADC) maps in differentiating radiological indeterminate vestibular schwannoma (VS) from meningioma in cerebellopontine angle (CPA). Diffusion-weighted (DW) images (b = 0 and 1000 s/mm 2 ) of pathologically confirmed and radiological indeterminate CPA meningioma (CPAM) (n = 27) and VS (n = 12) were retrospectively collected and processed with mono-exponential model. Whole-tumor regions of interest were drawn on all slices of the ADC maps to obtain histogram parameters, including the mean ADC (ADC mean ), median ADC (ADC median ), 10th/25th/75th/90th percentile ADC (ADC 10 , ADC 25 , ADC 75 and ADC 90 ), skewness and kurtosis. The differences of ADC histogram parameters between CPAM and VS were compared using unpaired t-test. Multiple receiver operating characteristic (ROC) curves analysis was used to determine and compare the diagnostic value of each significant parameter. Significant differences were found on the ADC mean , ADC median , ADC 10 , ADC 25 , ADC 75 and ADC 90 between CPAM and VS (all p values < 0.001), while no significant difference was found on kurtosis (p = 0.562) and skewness (p = 0.047). ROC curves analysis revealed, a cut-off value of 1.126 × 10 -3 mm 2 /s for the ADC 90 value generated highest area under curves (AUC) for differentiating CPAM from VS (AUC, 0.975; sensitivity, 100%; specificity, 88.9%). Histogram analysis of ADC maps based on whole tumor can be a useful tool for differentiating radiological indeterminate CPAM from VS. The ADC 90 value was the most promising parameter for differentiating these two entities.

Does One Size Fit Everyone? Replacement Dose of Levothyroxine in Long-standing Primary Hypothyroidism in Adults

PubMed Central

Singh, Rekha

2017-01-01

Objectives: The recommended starting dose of levothyroxine (LT4) in primary hypothyroidism is 1.6 μg/kg body weight and is based on presumption of minimal residual thyroid function in autoimmune hypothyroidism. This study aimed at finding the range and determining factors for LT4 dose in long-standing hypothyroidism. Methods: A cross-sectional study of individuals with primary autoimmune hypothyroidism on LT4 replacement was done between March 2015 and January 2016. Individuals enrolled were euthyroid based on recent serum thyroid-stimulating hormone. The inclusion criteria included LT4 intake in the morning empty stomach, maintenance of at least 1-h food gap, not on medications known to hamper LT4 absorption within 4 h of dosing, diagnosis of hypothyroidism at least for 1 year, and on a minimum 25 μg LT4. P < 0.05 was considered statistically significant. Results: A total of 346 individuals (290 women and 56 men; 214 premenopausal and 76 postmenopausal women) were enrolled. The mean duration of hypothyroidism and age were 5.7 years and 42.1 years, respectively. The range and mean of absolute LT4 daily dose (ADD), LT4 dose based on body weight (D/W), and LT4 dose based on ideal body weight (D/IBW) were 25–200 μg daily and 77.1 μg, 0.3–2.82 μg/kg and 1.21 μg/kg, and 0.42–3.5 μg/kg and 1.58 μg/kg, respectively. Duration of hypothyroidism was significant predictors of ADD, D/W, and D/IBW. Gender-based difference in ADD and D/IBW was explained by gender difference in anthropometry. Conclusion: Long-standing primary autoimmune hypothyroidism has variable dose requirement of LT4 for achieving euthyroidism and may be dependent on the degree of residual functional thyroid. Duration of hypothyroidism was significant positive predictor for either ADD, D/W, or D/IBW. PMID:28553595

Carbon balance and productivity of Lemna gibba, a candidate plant for CELSS.

PubMed

Gale, J; Smernoff, D T; Macler, B A; MacElroy, R D

1989-01-01

The photosynthesis and productivity of Lemna gibba were studied with a view to its use in Controlled Ecological Life Support Systems (CELSS). Photosynthesis of L. gibba floating on the nutrient solution could be driven by light coming from either above or below. Light from below was about 75% as effective as from above when the stand was sparse, but much less so with dense stands. High rates of photosynthesis (ca. 800 nanomoles CO2 g dry weight (DW)-1 s-1) were measured at 750 micromoles m-2 s-1 PPF and 1500 micromoles mol-1 CO2. This was attained at densities up to 660 g fresh weight (FW) m-2 with young cultures. After a few days growth under these conditions, and at higher densities, the rate of photosynthesis dropped to less than 25% of the initial value. This drop was only partly alleviated by thinning the stand or by introducing a short dark period at high temperature (26 degrees C). Despite the drop in the rate of photosynthesis, maximum yields were obtained in batch cultures grown under continuous light, constant temperature and high [CO2]. Plant protein content was less than reported for field grown Lemna. When the plants were harvested daily, maintaining a stand density of 600 g FW m-2, yields of 18 g DW m-2 d-1 were obtained. The total dry weight of L. gibba included 40% soluble material (sugars and amino acids), 15% protein, 5% starch, 5% ash and 35% cellulose and other polymers. We conclude that a CELSS system could be designed around stacked, alternate layers of transparent Lemna trays and lamps. This would allow for 7 tiers per meter height. Based on present data from single layers, the yield of such a system is calculated to be 135 g DW m-3 d-1 of a 100% edible, protein-rich food.

Occurrence of priority organic pollutants in the fertilizers, China.

PubMed

Mo, Ce-Hui; Cai, Quan-Ying; Li, Yun-Hui; Zeng, Qiao-Yun

2008-04-15

The use of large quantities of chemical fertilizers is usually associated with environmental problems. A lot of work has been done on the concentrations of heavy metals and radionuclides in chemical fertilizers, but little work has focused on the occurrence of semi-volatile organic compounds (SVOCs). In this study the occurrence of 43 SVOCs listed as priority pollutants in 22 widely used-fertilizers of China was determined by gas chromatography coupled with mass spectrometry. Twenty-six SVOCs were detected with different detection frequencies and concentrations. The most abundant compounds were phthalic acid esters (PAEs; ranging from 1.17 to 2795 microg kg(-1) dry weight, d.w.) and nitroaromatics (up to 9765 microg kg(-1) d.w.), followed by polycyclic aromatic hydrocarbons (PAHs; <140 microg kg(-1) d.w.) and halogenated hydrocarbons (<900 microg kg(-1) d.w.). Chlorobenzenes and haloethers occurred generally at low concentrations. There are large variations in concentrations of various compounds in different fertilizers, and the total concentrations of each class of contaminants varied widely, too. The highest levels of sum concentration for 16 PAHs, for 6 PAEs and for nitroaromatics were found in organic fertilizer containing pesticide and soil amendments. Concentrations of SVOCs in coated fertilizers (the controlled release fertilizer with coating) were considerably higher than those in the corresponding fertilizers without coating. The occurrence frequencies of SVOCs in the straight fertilizers (containing only one of the major plant nutrients) were lower than in the other fertilizers.

Salt marsh and seagrass communities of Bakkhali Estuary, Cox's Bazar, Bangladesh

NASA Astrophysics Data System (ADS)

Hena, M. K. Abu; Short, F. T.; Sharifuzzaman, S. M.; Hasan, M.; Rezowan, M.; Ali, M.

2007-10-01

The species identification, distribution pattern, density and biomass of salt marsh and seagrass plants with some of the ecological parameters were studied in the Bakkhali river estuary, Cox's Bazar, Bangladesh during the first half of 2006. Two salt marsh species ( Spartina sp. and Imperata cylindrica) and one seagrass species ( Halophila beccarii) were identified during this investigation, providing the first reports of Spartina sp. and H. beccarii in coastal Bangladesh. Seagrass H. beccarii was found in an accreted area and co-existing with salt marsh, and scattered sparsely in the salt marsh habitat and macroalgae Ulva intestinalis. Flowering and fruiting were recorded from the seagrass H. beccarri during January and February. No flowers and fruits were observed for the salt marsh Spartina sp. during the study period. Results showed that the shoot density of Spartina ranged from 400 to 2875 shoots m -2 with the highest total biomass (165.80 g dry weight (DW) m -2) in March. Shoot density of H. beccarii ranged from 2716 to 14320 shoots m -2 in this estuarine coastal environment. The total biomass of seagrass was higher (17.56 g DW m -2) in March compared to the other months. The highest H. beccarii above ground (AG) biomass and below ground (BG) biomass were 9.59 g DW m -2 and 9.42 g DW m -2, respectively. These parameters are comparable with those generally observed for the salt marsh and seagrass species in the other places of the world.

Characterisation of Mediterranean grape pomace seed and skin extracts: polyphenolic content and antioxidant activity.

PubMed

Ky, Isabelle; Teissedre, Pierre-Louis

2015-01-29

Grape pomace seeds and skins from different Mediterranean varieties (Grenache [GRE], Syrah [SYR], Carignan [CAR], Mourvèdre [MOU] and Alicante [ALI]) were extracted using water and water/ethanol 70% in order to develop edible extracts (an aqueous extract [EAQ] and a 70% hydro-alcoholic extract [EA70]) for potential use in nutraceutical or cosmetic formulations. In this study, global content (total polyphenols, total anthocyanins and total tannins), flavan-3-ols and anthocyanins were assessed using HPLC-UV-Fluo-MSn. In addition, extract potential was evaluated by four different assays: Oxygen Radical Absorbance Capacity (ORAC), Ferric Reducing Antioxidant Potential assay (FRAP), Trolox equivalent antioxidant capacity (TEAC) or ABTS assay and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. As expected, seed pomace extracts contained higher amounts of polyphenols then skin pomace extracts. Indeed, seeds from Syrah contained a particularly important amount of total polyphenols and tannins in both type of extract (up to 215.84 ± 1.47 mg of gallic acid equivalent [GAE]/g dry weight (DW) and 455.42 ± 1.84 mg/g DW, respectively). These extracts also expressed the highest antioxidant potential with every test. For skins, the maximum total phenolic was found in Alicante EAQ (196.71 ± 0.37 mg GAE/g DW) and in Syrah EA70 (224.92 ± 0.18 mg GAE/g DW). Results obtained in this article constitute a useful tool for the pre-selection of grape pomace seed and skin extracts for nutraceutical purposes.

SU-F-18C-12: On the Relationship of the Weighted Dose to the Surface Dose In Abdominal CT - Patient Size Dependency

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, Y; Scott, A; Allahverdian, J

2014-06-15

Purpose: It is possible to measure the patient surface dose non-invasively using radiolucent dosimeters. However, the patient size specific weighted dose remains unknown. We attempted to study the weighted dose to surface dose relationship as the patient size varies in abdominal CT. Methods: Seven abdomen phantoms (CIRS TE series) simulating patients from an infant to a large adult were used. Size specific doses were measured with a 100 mm CT chamber under axial scans using a Siemens Sensation 64 (mCT) and a GE 750 HD. The scanner settings were 120 kVp, 200 mAs with fully opened collimations. Additional kVps (80,more » 100, 140) were added depending on the phantom sizes. The ratios (r) of the weighted CT dose (Dw) to the surface dose (Ds) were related to the phantom size (L) defined as the diameter resulting the equivalent cross-sectional area. Results: The Dw versus Ds ratio (r) was fitted to a linear relationship: r = 1.083 − 0.007L (R square = 0.995), and r = 1.064 − 0.007L (R square = 0.953), for Siemens Sensation 64 and GE 750 HD, respectively. The relationship appears to be independent of the scanner specifics. Conclusion: The surface dose to the weighted dose ratio decreases linearly as the patient size increases. The result is independent of the scanner specifics. The result can be used to obtain in vivo CT dosimetry in abdominal CT.« less

Maternal Arsenic Exposure, Arsenic Methylation Efficiency, and Birth Outcomes in the Biomarkers of Exposure to ARsenic (BEAR) Pregnancy Cohort in Mexico

PubMed Central

Laine, Jessica E.; Bailey, Kathryn A.; Rubio-Andrade, Marisela; Olshan, Andrew F.; Smeester, Lisa; Drobná, Zuzana; Herring, Amy H.; Stýblo, Miroslav; García-Vargas, Gonzalo G.

2014-01-01

Background: Exposure to inorganic arsenic (iAs) from drinking water is a global public health problem, yet much remains unknown about the extent of exposure in susceptible populations. Objectives: We aimed to establish the Biomarkers of Exposure to ARsenic (BEAR) prospective pregnancy cohort in Gómez Palacio, Mexico, to better understand the effects of iAs exposure on pregnant women and their children. Methods: Two hundred pregnant women were recruited for this study. Concentrations of iAs in drinking water (DW-iAs) and maternal urinary concentrations of iAs and its monomethylated and dimethylated metabolites (MMAs and DMAs, respectively) were determined. Birth outcomes were analyzed for their relationship to DW-iAs and to the concentrations and proportions of maternal urinary arsenicals. Results: DW-iAs for the study subjects ranged from < 0.5 to 236 μg As/L. More than half of the women (53%) had DW-iAs that exceeded the World Health Organization’s recommended guideline of 10 μg As/L. DW-iAs was significantly associated with the sum of the urinary arsenicals (U-tAs). Maternal urinary concentrations of MMAs were negatively associated with newborn birth weight and gestational age. Maternal urinary concentrations of iAs were associated with lower mean gestational age and newborn length. Conclusions: Biomonitoring results demonstrate that pregnant women in Gómez Palacio are exposed to potentially harmful levels of DW-iAs. The data support a relationship between iAs metabolism in pregnant women and adverse birth outcomes. The results underscore the risks associated with iAs exposure in vulnerable populations. Citation: Laine JE, Bailey KA, Rubio-Andrade M, Olshan AF, Smeester L, Drobná Z, Herring AH, Stýblo M, García-Vargas GG, Fry RC. 2015. Maternal arsenic exposure, arsenic methylation efficiency, and birth outcomes in the Biomarkers of Exposure to ARsenic (BEAR) pregnancy cohort in Mexico. Environ Health Perspect 123:186–192; http://dx.doi.org/10.1289/ehp.1307476 PMID:25325819

Free-breathing diffusion tensor imaging and tractography of the human heart in healthy volunteers using wavelet-based image fusion.

PubMed

Wei, Hongjiang; Viallon, Magalie; Delattre, Benedicte M A; Moulin, Kevin; Yang, Feng; Croisille, Pierre; Zhu, Yuemin

2015-01-01

Free-breathing cardiac diffusion tensor imaging (DTI) is a promising but challenging technique for the study of fiber structures of the human heart in vivo. This work proposes a clinically compatible and robust technique to provide three-dimensional (3-D) fiber architecture properties of the human heart. To this end, 10 short-axis slices were acquired across the entire heart using a multiple shifted trigger delay (TD) strategy under free breathing conditions. Interscan motion was first corrected automatically using a nonrigid registration method. Then, two post-processing schemes were optimized and compared: an algorithm based on principal component analysis (PCA) filtering and temporal maximum intensity projection (TMIP), and an algorithm that uses the wavelet-based image fusion (WIF) method. The two methods were applied to the registered diffusion-weighted (DW) images to cope with intrascan motion-induced signal loss. The tensor fields were finally calculated, from which fractional anisotropy (FA), mean diffusivity (MD), and 3-D fiber tracts were derived and compared. The results show that the comparison of the FA values (FA(PCATMIP) = 0.45 ±0.10, FA(WIF) = 0.42 ±0.05, P=0.06) showed no significant difference, while the MD values ( MD(PCATMIP)=0.83 ±0.12×10(-3) mm (2)/s, MD(WIF)=0.74±0.05×10(-3) mm (2)/s, P=0.028) were significantly different. Improved helix angle variations through the myocardium wall reflecting the rotation characteristic of cardiac fibers were observed with WIF. This study demonstrates that the combination of multiple shifted TD acquisitions and dedicated post-processing makes it feasible to retrieve in vivo cardiac tractographies from free-breathing DTI acquisitions. The substantial improvements were observed using the WIF method instead of the previously published PCATMIP technique.

Estimating dead wood during national forest inventories: a review of inventory methodologies and suggestions for harmonization.

PubMed

Woodall, Christopher W; Rondeux, Jacques; Verkerk, Pieter J; Ståhl, Göran

2009-10-01

Efforts to assess forest ecosystem carbon stocks, biodiversity, and fire hazards have spurred the need for comprehensive assessments of forest ecosystem dead wood (DW) components around the world. Currently, information regarding the prevalence, status, and methods of DW inventories occurring in the world's forested landscapes is scattered. The goal of this study is to describe the status, DW components measured, sample methods employed, and DW component thresholds used by national forest inventories that currently inventory DW around the world. Study results indicate that most countries do not inventory forest DW. Globally, we estimate that about 13% of countries inventory DW using a diversity of sample methods and DW component definitions. A common feature among DW inventories was that most countries had only just begun DW inventories and employ very low sample intensities. There are major hurdles to harmonizing national forest inventories of DW: differences in population definitions, lack of clarity on sample protocols/estimation procedures, and sparse availability of inventory data/reports. Increasing database/estimation flexibility, developing common dimensional thresholds of DW components, publishing inventory procedures/protocols, releasing inventory data/reports to international peer review, and increasing communication (e.g., workshops) among countries inventorying DW are suggestions forwarded by this study to increase DW inventory harmonization.

Coresets vs clustering: comparison of methods for redundancy reduction in very large white matter fiber sets

NASA Astrophysics Data System (ADS)

Alexandroni, Guy; Zimmerman Moreno, Gali; Sochen, Nir; Greenspan, Hayit

2016-03-01

Recent advances in Diffusion Weighted Magnetic Resonance Imaging (DW-MRI) of white matter in conjunction with improved tractography produce impressive reconstructions of White Matter (WM) pathways. These pathways (fiber sets) often contain hundreds of thousands of fibers, or more. In order to make fiber based analysis more practical, the fiber set needs to be preprocessed to eliminate redundancies and to keep only essential representative fibers. In this paper we demonstrate and compare two distinctive frameworks for selecting this reduced set of fibers. The first framework entails pre-clustering the fibers using k-means, followed by Hierarchical Clustering and replacing each cluster with one representative. For the second clustering stage seven distance metrics were evaluated. The second framework is based on an efficient geometric approximation paradigm named coresets. Coresets present a new approach to optimization and have huge success especially in tasks requiring large computation time and/or memory. We propose a modified version of the coresets algorithm, Density Coreset. It is used for extracting the main fibers from dense datasets, leaving a small set that represents the main structures and connectivity of the brain. A novel approach, based on a 3D indicator structure, is used for comparing the frameworks. This comparison was applied to High Angular Resolution Diffusion Imaging (HARDI) scans of 4 healthy individuals. We show that among the clustering based methods, that cosine distance gives the best performance. In comparing the clustering schemes with coresets, Density Coreset method achieves the best performance.

Medium-Chain Chlorinated Paraffins (CPs) Dominate in Australian Sewage Sludge.

PubMed

Brandsma, Sicco H; van Mourik, Louise; O'Brien, Jake W; Eaglesham, Geoff; Leonards, Pim E G; de Boer, Jacob; Gallen, Christie; Mueller, Jochen; Gaus, Caroline; Bogdal, Christian

2017-03-21

To simultaneously quantify and profile the complex mixture of short-, median-, and long-chain CPs (SCCPs, MCCPs, and LCCPs) in Australian sewage sludge, we applied and further validated a recently developed novel instrumental technique, using quadrupole time-of-flight high resolution mass spectrometry running in the negative atmospheric pressure chemical ionization mode (APCI-qTOF-HRMS). Without using an analytical column the cleaned extracts were directly injected into the qTOF-HRMS followed by quantification of the CPs by a mathematical algorithm. The recoveries of the four SCCP, MCCP and LCCP-spiked sewage sludge samples ranged from 86 to 123%. This APCI-qTOF-HRMS method is a fast and promising technique for routinely measuring SCCPs, MCCPs, and LCCPs in sewage sludge. Australian sewage sludge was dominated by MCCPs with concentrations ranging from 542 to 3645 ng/g dry weight (dw). Lower SCCPs concentrations (<57-1421 ng/g dw) were detected in the Australian sewage sludge, which were comparable with the LCCPs concentrations (116-960 ng/g dw). This is the first time that CPs were reported in Australian sewage sludge. The results of this study gives a first impression on the distribution of the SCCPs, MCCPs, and LCCPs in Australia wastewater treatment plants (WWTPs).

Mercury in soil and perennial plants in a mining-affected urban area from Northwestern Romania.

PubMed

Senilă, Marin; Levei, Erika A; Senilă, Lăcrimioara R; Oprea, Gabriela M; Roman, Cecilia M

2012-01-01

The mercury (Hg) concentrations were evaluated in soils and perennial plants sampled in four districts of Baia Mare city, a historical mining and ore processing center in Northwestern Romania. The results showed that the Hg concentration exceeded the guideline value of 1.0 mg kg(-1) dry weight (dw) established by the Romanian Legislation, in 24 % of the analyzed soil samples, while the median Hg concentration (0.70 mg kg(-1) dw) was lower than the guideline value. However, Hg content in soil was generally higher than typical values in soils from residential and agricultural areas of the cities all over the world. The median Hg concentration was 0.22 mg kg(-1) dw in the perennial plants, and exceeded the maximum level of Hg (0.10 mg kg(-1)) established by European Directive 2002/32/EC for plants used in animal feed in order to prevent its transfer and further accumulation in the higher levels of food chain. No significant correlations were found between soil Hg and other analyzed metals (Cd, Cu, Pb, Zn) resulted from the non-ferrous smelting activities, probably due to the different physicochemical properties, that led to different dispersion patterns.

Chemical characterisation and speciation of organic selenium in cultivated selenium-enriched Agaricus bisporus.

PubMed

Maseko, Tebo; Callahan, Damien L; Dunshea, Frank R; Doronila, Augustine; Kolev, Spas D; Ng, Ken

2013-12-15

The selenium concentration in Agaricus bisporus cultivated in growth compost irrigated with sodium selenite solution increased by 28- and 43-fold compared to the control mushroom irrigated solely with water. Selenium contents of mushroom proteins increased from 13.8 to 60.1 and 14.1 to 137 μgSe/g in caps and stalks from control and selenised mushrooms, respectively. Selenocystine (SeCys; detected as [SeCys]2 dimer), selenomethionine (SeMet), and methyl-selenocysteine (MeSeCys) were separated, identified and quantified by liquid chromatography-electrospray ionisation-mass spectrometry from water solubilised and acetone precipitated proteins, and significant increases were observed for the selenised mushrooms. The maximum selenoamino acids concentration in caps and stalks of control/selenised mushrooms was 4.16/9.65 μg/g dried weight (DW) for SeCys, 0.08/0.58 μg/g DW for SeMet, and 0.031/0.10 μg/g DW for MeSeCys, respectively. The most notable result was the much higher levels of SeCys accumulated by A. bisporus compared to SeMet and MeSeCys, for both control and selenised A. bisporus. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

Survey of cotton (Gossypium sp.) for non-polar, extractable hydrocarbons for use as petrochemicals and liquid fuels

USDA-ARS?s Scientific Manuscript database

An ontogenetic study of a commercial cotton cultivar (FiberMax 1320), grown dryland, revealed that the dry weight (DW) of leaves reached a maximum at the 1st flower stage, and then declined as bolls opened. However, % pentane soluble hydrocarbon (HC) yield continued to increase throughout the growi...

Fall nitrogen fertilization and the biology of Pinus taeda seedling development

Treesearch

Shi-Jean S. Sung; C.C. Black; T.L. Kormanik; P.A. Counce

1997-01-01

In mid-September when stems and roots of nursery-grown loblolly pine (Pinus taeda L.) seedlings are actively accumulating dry weight (DW), an extra 10, 20, or 40 kg NH4NO3 ha-1 (10N, 20N, 4ON) was applied. Seedlings receiving no extra N (0N) were the controls. The temporal patterns...

Effect of a carbohydrate-electrolyte beverage, lemon tea, or water on rehydration during short-term recovery from exercise.

PubMed

Wong, Stephen Heung-Sang; Chen, Yajun

2011-08-01

This study examined the rehydration achieved by drinking different beverages during a short-term recovery period (REC) after exercise-induced dehydration. Thirteen well-trained men (age 22.1 ± 3.3 yr, body mass 61.2 ± 9.1 kg, VO(2max) 64.9 ± 4.0 ml · kg-1 · min-1, maximum heart rate 198 ± 7 beats/min) ran for 60 min on 3 occasions on a level treadmill at 70% VO(2max). All trials were performed in thermoneutral conditions (21 °C, 71% relative humidity) and were separated by at least 7 d. During 4 hr REC, the subjects consumed either a volume of a carbohydrate-electrolyte beverage (CE), lemon tea (LT), or distilled water (DW) equal to 150% of the body weight (BW) lost during the previous run. The fluid was consumed in 6 equal volumes at 30, 60, 90, 120, 150, and 180 min of REC. After the completion of the 60-min run, the subjects lost ~2.0% of their preexercise BW in all trials, and no differences were observed in these BW changes between trials. At the end of REC, the greatest fraction of the retained drink occurred when the CE drink was consumed (CE vs. LT vs. DW: 52% ± 18% vs. 36% ± 15% vs. 30% ± 14%, p < .05). The CE drink also caused the least diuretic effect (CE vs. LT vs. DW: 638 ± 259 vs. 921 ± 323 vs. 915 ± 210 ml, p < .05) and produced the optimal restoration of plasma volume (CE vs. LT vs. DW: 11.2% ± 2.0% vs. -3.1% ± 1.8% vs. 0.2% ± 2.1%, p < .05). The results of this study suggest that CE drinks are more effective than DW or LT in restoring fluid balance during short-term REC after exercise-induced dehydration.

Compost-based growing media: influence on growth and nutrient use of bedding plants.

PubMed

Grigatti, Marco; Giorgioni, Maria Eva; Ciavatta, Claudio

2007-12-01

The agronomic performance and the mineral composition and trace element content in Begonia semperflorens "Bellavista F1", Mimulus "Magic x hybridus", Salvia splendens "maestro", and Tagete patula xerecta "Zenith Lemon Yellow", were tested by growing the plants on substrates of white peat and 25-50-75-100% green waste and sewage sludge (80%+20%v/v) compost (CP). A commercial peat medium of black and white peat (2:1v/v) was used as control. At flowering, the agronomic parameters were compared by ANOVA and plant nutritional status was compared by vector analysis. Substrate-species interactions (P<0.001) were evident for all measured parameters. In the 25% CP medium all the species showed an increase or preservation of the studied agronomic parameters. Begonia grown in 25% CP, showed the highest dry weight (DW) and number of flowers. Other treatments were comparable to the control. Mimulus and Salvia showed the highest DW in the 25-50% CP. Mimulus, after a DW increase up to 50% CP, showed the steepest reduction as the CP increased further. Tagete showed no differences in DW up to 50% CP, or in flower number up to 25% CP, compared to the control. The additional increases of CP in the medium showed a DW decrease similar to that of Salvia. Vector analysis showed the use of compost mainly induced a decrease of P concentration in tissues, except for Begonia which remained unchanged. Plant tissues showed a general P reduction due to a dilution effect in the low compost mixtures (25-50%) and a deficiency in the higher CP mixtures. In contrast, an increase of Mg in the aboveground tissues of all species was detectable as compost usage increased, with the exception of Salvia which suffered a Mg deficiency. Vector analysis also highlighted a Ni and partial Fe deficiency in Tagete and Salvia.

Occurrence, distribution and sources of organochlorine pesticides (OCPs) in surface sediments from the Lijiang River, a typical karst river of southwestern China.

PubMed

Zhang, Dan; Wang, Yinghui; Yu, Kefu; Li, Pingyang; Zhang, Ruijie; Xu, Yiyin

2014-11-01

The Lijiang River is a typical karst river of southwestern China. Karst-aquifer systems are more vulnerable to contamination compared to other types of aquifers. The occurrence and distribution of organochlorine pesticides (OCPs) in surface sediments from the Lijiang River were investigated to evaluate their potential ecological risks. The total concentrations of them in sediments ranged from 0.80 to 18.73 ng/g dry weight (dw) (mean 6.83 ng/g dw). The residue levels of OCPs varied in the order of HCB > HCHs > DDTs. Compositional analyses of OCPs showed that HCHs and DDTs were mainly from historical usage. The ecological risk assessment suggested that HCHs and DDTs in Lijiang River sediments may cause adverse ecological risks, particularly at sites near agricultural areas.

The effects of Vitamin C on sperm quality parameters in laboratory rats following long-term exposure to cyclophosphamide.

PubMed

Shabanian, Sheida; Farahbod, Farnoosh; Rafieian, Mahmoud; Ganji, Forouzan; Adib, Afshin

2017-01-01

Cyclophosphamide is a widely used medication and can cause oxidative stress. This study was conducted to investigate the effects of Vitamin C on reproductive organs' weight and the quality of sperm parameters in laboratory rats. In this experimental study, 40 rats were randomly assigned into five groups of eight each. Distilled water (DW) group received only food and water, Group 2 was administered with drug solvent (DW) by gavage, Group 3 intraperitoneally administered with 1.6 mg/kg cyclophosphamide, Group 4 gavaged Vitamin C at 0.88 mg/kg, and Group 5 administered with effective doses of Vitamin C and cyclophosphamide by gavage with 1-h intervals. Sperm parameters of the samples were taken from distal epididymis and tissues were studied, and the data were analyzed by SPSS version 22. The lowest weight of testicles and epididymis was seen in cyclophosphamide-exposed rats and the highest weight of testicles and epididymis in Vitamin C-exposed rats ( P < 0.05). The highest motility, progression, viability, and count of sperm were seen in the Vitamin C-treated group and the lowest in the cyclophosphamide-exposed group. The highest proportion of sperm anomalies was seen in the cyclophosphamide-exposed group. Vitamin C, as an antioxidant, can be effective on some of the sperm parameters and can reduce cyclophosphamide-induced complications in animal model.

The effects of Vitamin C on sperm quality parameters in laboratory rats following long-term exposure to cyclophosphamide

PubMed Central

Shabanian, Sheida; Farahbod, Farnoosh; Rafieian, Mahmoud; Ganji, Forouzan; Adib, Afshin

2017-01-01

Cyclophosphamide is a widely used medication and can cause oxidative stress. This study was conducted to investigate the effects of Vitamin C on reproductive organs' weight and the quality of sperm parameters in laboratory rats. In this experimental study, 40 rats were randomly assigned into five groups of eight each. Distilled water (DW) group received only food and water, Group 2 was administered with drug solvent (DW) by gavage, Group 3 intraperitoneally administered with 1.6 mg/kg cyclophosphamide, Group 4 gavaged Vitamin C at 0.88 mg/kg, and Group 5 administered with effective doses of Vitamin C and cyclophosphamide by gavage with 1-h intervals. Sperm parameters of the samples were taken from distal epididymis and tissues were studied, and the data were analyzed by SPSS version 22. The lowest weight of testicles and epididymis was seen in cyclophosphamide-exposed rats and the highest weight of testicles and epididymis in Vitamin C-exposed rats (P < 0.05). The highest motility, progression, viability, and count of sperm were seen in the Vitamin C-treated group and the lowest in the cyclophosphamide-exposed group. The highest proportion of sperm anomalies was seen in the cyclophosphamide-exposed group. Vitamin C, as an antioxidant, can be effective on some of the sperm parameters and can reduce cyclophosphamide-induced complications in animal model. PMID:28516060

Contaminants in molting long-tailed ducks and nesting common eiders in the Beaufort Sea

USGS Publications Warehouse

Franson, J.C.; Hollmén, Tuula E.; Flint, Paul L.; Grand, J.B.; Lanctot, Richard B.

2004-01-01

In 2000, we collected blood from long-tailed ducks (Clangula hyemalis) and blood and eggs from common eiders (Somateria mollissima) at near-shore islands in the vicinity of Prudhoe Bay, Alaska, and at a reference area east of Prudhoe Bay. Blood was analyzed for trace elements and egg contents were analyzed for trace elements, organochlorine pesticides, polychlorinated biphenyls, and polycyclic aromatic hydrocarbons. Except for Se (mean=36.1 ??g/g dry weight (dw) in common eiders and 48.8 ??g/g dw in long-tailed ducks), concentrations of trace elements in blood were low and, although several trace elements differed between areas, they were not consistently higher at one location. In long-tailed ducks, Se in blood was positively correlated with activities of two serum enzymes, suggestive of an adverse effect of increasing Se levels on the liver. Although common eiders had high Se concentrations in their blood, Se residues in eggs were low (mean=2.28 ??g/g dw). Strontium and Ni were higher in eggs near Prudhoe Bay than at the reference area, but none of the other trace elements or organic contaminants in eggs differed between locations. Concentrations of Ca, Sr, Mg, and Ni differed among eggs having no visible development, early-stage embryos, or late-stage embryos. Residues of 4,4???-DDE, cis-nonachlor, dieldrin, hexachlorobenzene, oxychlordane, and trans-nonachlor were found in 100% of the common eider eggs, but at low concentrations (means of 2.35-7.45 ??g/kg wet weight (ww)). The mean total PCB concentration in eggs was 15.12 ??g/kg ww. Of PAHs tested for, residues of 1- and 2-methylnaphthalene and naphthalene were found in 100% of the eggs, at mean concentrations of 0.36-0.89 ??g/kg ww.

Individual and combined effects of cadmium and diesel on a nematode community in a laboratory microcosm experiment.

PubMed

Beyrem, H; Mahmoudi, E; Essid, N; Hedfi, A; Boufahja, F; Aïssa, P

2007-11-01

A microcosm experiment was carried out to study the influence of cadmium and diesel, individually and in a mixture, on a free living nematode community of a Tunisian lagoon. Sediments were contaminated with cadmium that ranged in concentration from 0.54 to 1.40 mg Cd kg(-1) (dry weight (dw)), by diesel at 0.25 mg kg(-1) (dw), by a cadmium-diesel mixture (Cd at 1.40 mg kg(-1)+Diesel at 0.25 mg kg(-1)) and effects were examined after 90 days. Univariate analysis showed that all univariate indices did not change significantly neither at all the levels of cadmium contamination nor at 0.25 mg kg(-1) (dw) diesel concentration. But, at the cadmium-diesel mixture, significant differences were recorded between nematode assemblages from uncontaminated sediment control microcosm and those from cadmium-diesel mixture amended sediment treatments. Total nematode abundance (I), mean individual weight (bi), Shannon-Weaver index H', species richness (d), evenness (J') and number of species (S) decreased significantly in microcosms contaminated with both cadmium and diesel. Results from multivariate analyses of the species abundance data demonstrated that responses of nematode species to the cadmium-diesel treatments were varied: Marylynnia stekhoveni, Calomicrolaimus honestus and Oncholaimellus mediterraneus were significantly affected at the cadmium-diesel contamination but they were not eliminated. These species could be categorized as "cadmium-diesel sensitive". Enoploides sp. and Oncholaimus campylocercoides, characterized by increased abundances in cadmium-diesel amended sediment, seemed to be "cadmium-diesel resistant" species. All these species, "cadmium-diesel sensitive" or "cadmium-diesel resistant", were not affected by either cadmium or diesel alone.

Arsenic speciation in tissues of the hyperaccumulator P. calomelanos var. austroamericana using X-ray absorption spectroscopy.

PubMed

Kachenko, Anthony G; Gräfe, Markus; Singh, Balwant; Heald, Steve M

2010-06-15

The fate and chemical speciation of arsenic (As) during uptake, translocation, and storage by the As hyperaccumulating fern Pityrogramma calomelanos var. austroamericana (Pteridaceae) were examined using inductively coupled plasma-atomic emission spectrometry (ICP-AES) and synchrotron-based micro-X-ray absorption near edge structure (micro-XANES) and micro-X-ray fluorescence (micro-XRF) spectroscopies. Chemical analysis revealed total As concentration was ca. 6.5 times greater in young fronds (5845 mg kg(-1) dry weight (DW)) than in old fronds (903 mg kg(-1) DW). In pinnae, As concentration decreased from the base (6822 mg kg(-1) DW) to the apex (4301 mg kg(-1) DW) of the fronds. The results from micro-XANES and micro-XRF of living tissues suggested that more than 60% of arsenate (As(V)) absorbed was reduced to arsenite (As(III)) in roots, prior to transport through vascular tissues as As(V) and As(III). In pinnules, As(III) was the predominant redox species (72-90%), presumably as solvated, oxygen coordinated compounds. The presence of putative As(III)-sulphide (S(2-)) coordination throughout the fern tissues (4-25%) suggests that S(2-) functional groups may contribute in the biochemical reduction of As(V) to As(III) during uptake and transport at a whole-plant level. Organic arsenicals and thiol-rich compounds were not detected in the species and are unlikely to play a role in As hyperaccumulation in this fern. The study provides important insights into homeostatic regulation of As following As uptake in P. calomelanos var. austroamericana.

Metabolic costs and evolutionary implications of human brain development

PubMed Central

Kuzawa, Christopher W.; Chugani, Harry T.; Grossman, Lawrence I.; Lipovich, Leonard; Muzik, Otto; Hof, Patrick R.; Wildman, Derek E.; Sherwood, Chet C.; Leonard, William R.; Lange, Nicholas

2014-01-01

The high energetic costs of human brain development have been hypothesized to explain distinctive human traits, including exceptionally slow and protracted preadult growth. Although widely assumed to constrain life-history evolution, the metabolic requirements of the growing human brain are unknown. We combined previously collected PET and MRI data to calculate the human brain’s glucose use from birth to adulthood, which we compare with body growth rate. We evaluate the strength of brain–body metabolic trade-offs using the ratios of brain glucose uptake to the body’s resting metabolic rate (RMR) and daily energy requirements (DER) expressed in glucose-gram equivalents (glucosermr% and glucoseder%). We find that glucosermr% and glucoseder% do not peak at birth (52.5% and 59.8% of RMR, or 35.4% and 38.7% of DER, for males and females, respectively), when relative brain size is largest, but rather in childhood (66.3% and 65.0% of RMR and 43.3% and 43.8% of DER). Body-weight growth (dw/dt) and both glucosermr% and glucoseder% are strongly, inversely related: soon after birth, increases in brain glucose demand are accompanied by proportionate decreases in dw/dt. Ages of peak brain glucose demand and lowest dw/dt co-occur and subsequent developmental declines in brain metabolism are matched by proportionate increases in dw/dt until puberty. The finding that human brain glucose demands peak during childhood, and evidence that brain metabolism and body growth rate covary inversely across development, support the hypothesis that the high costs of human brain development require compensatory slowing of body growth rate. PMID:25157149

Combination of a Fast Cleanup Procedure and a DR-CALUX® Bioassay for Dioxin Surveillance in Taiwanese Soils

PubMed Central

Lin, Ding-Yan; Lee, Yi-Pin; Li, Chiu-Ping; Chi, Kai-Hsien; Liang, Bo-Wei P.; Liu, Wen-Yao; Wang, Chih-Cheng; Lin, Susana; Chen, Ting-Chien; Yeh, Kuei-Jyum C.; Hsu, Ping-Chi; Hsu, Yi-Chyun; Chao, How-Ran; Tsou, Tsui-Chun

2014-01-01

Our goal was to determine dioxin levels in 800 soil samples collected from Taiwan. An in vitro DR-CALUX® assay was carried out with the help of an automated Soxhlet system and fast cleanup column. The mean dioxin level of 800 soil samples was 36.0 pg-bioanalytical equivalents (BEQs)/g dry weight (d.w.). Soil dioxin-BEQs were higher in northern Taiwan (61.8 pg-BEQ/g d.w.) than in central, southern, and eastern Taiwan (22.2, 24.9, and 7.80 pg-BEQ/g d.w., respectively). Analysis of multiple linear regression models identified four major predictors of dioxin-BEQs including soil sampling location (β = 0.097, p < 0.001), land use (β = 0.065, p < 0.001), soil brightness (β = 0.170, p < 0.001), and soil moisture (β = 0.051, p = 0.020), with adjusted R2 = 0.947 (p < 0.001) (n = 662). An univariate logistic regression analysis with the cut-off point of 33.4 pg-BEQ/g d.w. showed significant odds ratios (ORs) for soil sampling location (OR = 2.43, p < 0.001), land use (OR = 1.47, p < 0.001), and soil brightness (OR = 2.83, p = 0.009). In conclusion, four variables, including soil sampling location, land use, soil brightness, and soil moisture, may be related to soil-dioxin contamination. Soil samples collected in northern Taiwan, and especially in Bade City, soils near industrial areas, and soils with darker color may contain higher dioxin-BEQ levels. PMID:24806195

Effect of red and blue light emitting diodes "CRB-LED" on in vitro organogenesis of date palm (Phoenix dactylifera L.) cv. Alshakr.

PubMed

Al-Mayahi, Ahmed Madi Waheed

2016-10-01

The objective of the present study is to determine the effect of light source on enhancement of shoot multiplication, phytochemicals, as well as, antioxidant enzyme activities of in vitro cultures of date palm cv. Alshakr. In vitro-grown buds were cultured on Murashige and Skoog (MS) medium and incubated under a conventional white fluorescent light (control), and combinations of red + blue light emitting diode (18:2) (CRB-LED). Results revealed that the treatment of CRB-LED showed a significant increase in the number of shoots compared with the white florescent light. Total soluble carbohydrate "TSCH" (7.10 mg g(-1) DW.), starch (1.63 mg g(-1) DW.) and free amino acids (2.90 mg g(-1) DW.) were significantly higher in CRB-LED (p < 0.05). Additionally, CRB-LED induced a higher peroxidase activity (25.50 U ml(-1)) compared with the white fluorescent light treatment (19.74 U ml(-1)) as control treatment. Potassium, magnesium and sodium contents in (3.62, 13.99 and 2.76 mg g(-1) DW.) were increased in in vitro shoots under CRB-LED treatment in comparison with fluorescent light (p < 0.05). Protein profile showed the appearance of newly bands with the molecular weight of 38 and 60 kDa at the treatment CRB-LED compared with control treatment. Our results demonstrate the positive effects of CRB-LED light during the course of date palm tissue cultures.

Metabolic costs and evolutionary implications of human brain development.

PubMed

Kuzawa, Christopher W; Chugani, Harry T; Grossman, Lawrence I; Lipovich, Leonard; Muzik, Otto; Hof, Patrick R; Wildman, Derek E; Sherwood, Chet C; Leonard, William R; Lange, Nicholas

2014-09-09

The high energetic costs of human brain development have been hypothesized to explain distinctive human traits, including exceptionally slow and protracted preadult growth. Although widely assumed to constrain life-history evolution, the metabolic requirements of the growing human brain are unknown. We combined previously collected PET and MRI data to calculate the human brain's glucose use from birth to adulthood, which we compare with body growth rate. We evaluate the strength of brain-body metabolic trade-offs using the ratios of brain glucose uptake to the body's resting metabolic rate (RMR) and daily energy requirements (DER) expressed in glucose-gram equivalents (glucosermr% and glucoseder%). We find that glucosermr% and glucoseder% do not peak at birth (52.5% and 59.8% of RMR, or 35.4% and 38.7% of DER, for males and females, respectively), when relative brain size is largest, but rather in childhood (66.3% and 65.0% of RMR and 43.3% and 43.8% of DER). Body-weight growth (dw/dt) and both glucosermr% and glucoseder% are strongly, inversely related: soon after birth, increases in brain glucose demand are accompanied by proportionate decreases in dw/dt. Ages of peak brain glucose demand and lowest dw/dt co-occur and subsequent developmental declines in brain metabolism are matched by proportionate increases in dw/dt until puberty. The finding that human brain glucose demands peak during childhood, and evidence that brain metabolism and body growth rate covary inversely across development, support the hypothesis that the high costs of human brain development require compensatory slowing of body growth rate.

Performance Analysis of OCDMA Based on AND Detection in FTTH Access Network Using PIN & APD Photodiodes

NASA Astrophysics Data System (ADS)

Aldouri, Muthana; Aljunid, S. A.; Ahmad, R. Badlishah; Fadhil, Hilal A.

2011-06-01

In order to comprise between PIN photo detector and avalanche photodiodes in a system used double weight (DW) code to be a performance of the optical spectrum CDMA in FTTH network with point-to-multi-point (P2MP) application. The performance of PIN against APD is compared through simulation by using opt system software version 7. In this paper we used two networks designed as follows one used PIN photo detector and the second using APD photo diode, both two system using with and without erbium doped fiber amplifier (EDFA). It is found that APD photo diode in this system is better than PIN photo detector for all simulation results. The conversion used a Mach-Zehnder interferometer (MZI) wavelength converter. Also we are study, the proposing a detection scheme known as AND subtraction detection technique implemented with fiber Bragg Grating (FBG) act as encoder and decoder. This FBG is used to encode and decode the spectral amplitude coding namely double weight (DW) code in Optical Code Division Multiple Access (OCDMA). The performances are characterized through bit error rate (BER) and bit rate (BR) also the received power at various bit rate.

Using fecal sterols to assess dynamics of sewage input in sediments along a human-impacted river-estuary system in eastern China.

PubMed

He, Ding; Zhang, Kai; Tang, Jianhui; Cui, Xingqian; Sun, Yongge

2018-05-01

Sedimentary fecal sterols and other sterol biomarkers, combined with bulk total organic carbon (TOC) and its stable carbon isotope were applied to characterize the sewage contamination across a ca. 280 km transect from the Xiaoqing River to the Laizhou Bay, a typical river-estuary system subjected to extensive anthropogenic stress due to rapid regional urbanization and industrialization in eastern China. Two sampling events were performed in both spring and summer seasons in the Laizhou Bay adjacent to the Xiaoqing River in order to assess the potential seasonal variation. Fecal sterols such as coprostanol and epicoprostanol, which are typical indicators of anthropogenic sewage input, displayed high concentrations of up to 63.2 μg g -1 dry weight (dw) and 13.1 μg g -1 dw, respectively. Results suggested that most of the stations along the Xiaoqing River were severely contaminated by fecal inputs with a decreasing trend from the river to the estuary that was mainly explained by the increasing distance from the diffuse sewage sources and the gradual dilution by sea water. Although there was no significant difference in fecal sterol concentrations between spring and summer in the Laizhou Bay, suggestive of no significant difference in sewage abundance, significantly higher average epicoprostanol/coprostanol and lower coprostanol/epicoprostanol ratios were observed in spring than summer, indicative of different sewage sources (e.g., human vs. non-human). Seasonal discharge and land-runoff, air temperature related to microbial activity differences and different extend of animal manure irrigation during agricultural planting could be additional reasons and need further investigation. Nevertheless, fecal sterol concentrations, distributions and diagnostic ratios should all be taken into consideration to better understand sewage inputs and source dynamics in river-estuary ecosystems. Copyright © 2018 Elsevier B.V. All rights reserved.

Diffusion-weighted imaging of the breast: principles and clinical applications.

PubMed

Woodhams, Reiko; Ramadan, Saadallah; Stanwell, Peter; Sakamoto, Satoko; Hata, Hirofumi; Ozaki, Masanori; Kan, Shinichi; Inoue, Yusuke

2011-01-01

Diffusion-weighted imaging provides a novel contrast mechanism in magnetic resonance (MR) imaging and has a high sensitivity in the detection of changes in the local biologic environment. A significant advantage of diffusion-weighted MR imaging over conventional contrast material-enhanced MR imaging is its high sensitivity to change in the microscopic cellular environment without the need for intravenous contrast material injection. Approaches to the assessment of diffusion-weighted breast imaging findings include assessment of these data alone and interpretation of the data in conjunction with T2-weighted imaging findings. In addition, the analysis of apparent diffusion coefficient (ADC) value can be undertaken either in isolation or in combination with diffusion-weighted and T2-weighted imaging. Most previous studies have evaluated ADC value alone; however, overlap in the ADC values of malignant and benign disease has been observed. This overlap may be partly due to selection of b value, which can influence the concomitant effect of perfusion and emphasize the contribution of multicomponent model influences. The simultaneous assessment of diffusion-weighted and T2-weighted imaging data and ADC value has the potential to improve specificity. In addition, the use of diffusion-weighted imaging in a standard breast MR imaging protocol may heighten sensitivity and thereby improve diagnostic accuracy. Standardization of diffusion-weighted imaging parameters is needed to allow comparison of multicenter studies and assessment of the clinical utility of diffusion-weighted imaging and ADC values in breast evaluation.

A Potential New Threat to Wild Life: Presence of UV Filters in Bird Eggs from a Preserved Area.

PubMed

Molins-Delgado, Daniel; Máñez, Manuel; Andreu, Ana; Hiraldo, Fernando; Eljarrat, Ethel; Barceló, Damià; Díaz-Cruz, M Silvia

2017-10-03

The present study uses bird eggs of seven wild species as a biomonitoring tool for sunscreens occurrence. Seven UV filters (UV-Fs), including 3 hydroxy-metabolites of oxybenzone (benzophenone 3, BP3) were characterized in unhatched eggs from Doñana Natural Space (Spain). High frequency of detection was observed for all UV-Fs, ranging from 95% to 100%. The oxybenzone metabolite 4-hydroxybenzophenone (4HB) was ubiquitous at concentrations in the range 12.0-3348 ng g -1 dry weight (dw). The parent compound, oxybenzone, was also present in all samples at lower concentrations (16.9-49.3 ng g -1 dw). Due to the three BP3's metabolites, benzophenone 1 (BP1), 4HB, and 4,4'-dihydroxybenzophenone (4DHB) presence in unhatched eggs, it can be inferred that parent compounds are absorbed into the bird through the upper gut and the OH-derivatives formed are transferred by the mother to the egg before the lying. White stork (Ciconia ciconia) and western marsh harrier (Circus aeruginosus) were the most contaminated species, with mean total UV-Fs concentrations of 834 and 985 ng g -1 dw, respectively. Results evidenced that biomagnification process across the bird species studied cannot be ruled out.

In vitro biomonitoring of contamination by estrogenic compounds in coastal environments: comments on the use of M. galloprovincialis.

PubMed

David, Arthur; Fenet, Hélène; Escande, Aurélie; Munaron, Dominique; Rosain, David; Maillot-Maréchal, Emmanuelle; Aït-Aïssa, Selim; Casellas, Claude; Gomez, Elena

2012-02-01

The use of mussel extracts in in vitro bioassays which express the estrogen receptor could provide valuable information on the bioavailability of endocrine disruptors in coastal environments. The aim of this study was to assess the temporal variability of the estrogenic responses in bioassays in Mytilus galloprovincialis. A 6-month in situ experiment was conducted in order to follow the estrogenic activity on MELN cell line during the reproduction stages of mussels. Estradiol equivalents (EEQ) determined in mussels using the MELN cell lines ranged from 0.79 to 3.72 ng/g dry weight (d.w.) in males, from 0.42 to 2.33 ng/g d.w. in females and from 3.41 to 4.2 d.w. in undifferentiated bivalves. We observed an increase in EEQ values during the spawning stage for males, not for female. The maximal EEQ values were observed at the indifferent stage. We discuss these results in regards to the actual knowledge on mussels' reproductive cycle and to the possible impact of xeno-estrogens. Variations of E2 levels in mussels must be taken into account for further studies on xeno-estrogens monitoring using hER reporter cell-lines bioassays. Copyright © 2010 Wiley Periodicals, Inc.

Medium-Chain Chlorinated Paraffins (CPs) Dominate in Australian Sewage Sludge

PubMed Central

2017-01-01

To simultaneously quantify and profile the complex mixture of short-, median-, and long-chain CPs (SCCPs, MCCPs, and LCCPs) in Australian sewage sludge, we applied and further validated a recently developed novel instrumental technique, using quadrupole time-of-flight high resolution mass spectrometry running in the negative atmospheric pressure chemical ionization mode (APCI-qTOF-HRMS). Without using an analytical column the cleaned extracts were directly injected into the qTOF-HRMS followed by quantification of the CPs by a mathematical algorithm. The recoveries of the four SCCP, MCCP and LCCP-spiked sewage sludge samples ranged from 86 to 123%. This APCI-qTOF-HRMS method is a fast and promising technique for routinely measuring SCCPs, MCCPs, and LCCPs in sewage sludge. Australian sewage sludge was dominated by MCCPs with concentrations ranging from 542 to 3645 ng/g dry weight (dw). Lower SCCPs concentrations (<57–1421 ng/g dw) were detected in the Australian sewage sludge, which were comparable with the LCCPs concentrations (116–960 ng/g dw). This is the first time that CPs were reported in Australian sewage sludge. The results of this study gives a first impression on the distribution of the SCCPs, MCCPs, and LCCPs in Australia wastewater treatment plants (WWTPs). PMID:28218842

Chemical and Nutritional Composition of Terminalia ferdinandiana (Kakadu Plum) Kernels: A Novel Nutrition Source

PubMed Central

Netzel, Michael E.; Tinggi, Ujang

2018-01-01

Terminalia ferdinandiana (Kakadu plum) is a native Australian fruit. Industrial processing of T. ferdinandiana fruits into puree generates seeds as a by-product, which are generally discarded. The aim of our present study was to process the seed to separate the kernel and determine its nutritional composition. The proximate, mineral and fatty acid compositions were analysed in this study. Kernels are composed of 35% fat, while proteins account for 32% dry weight (DW). The energy content and fiber were 2065 kJ/100 g and 21.2% DW, respectively. Furthermore, the study showed that kernels were a very rich source of minerals and trace elements, such as potassium (6693 mg/kg), calcium (5385 mg/kg), iron (61 mg/kg) and zinc (60 mg/kg) DW, and had low levels of heavy metals. The fatty acid composition of the kernels consisted of omega-6 fatty acid, linoleic acid (50.2%), monounsaturated oleic acid (29.3%) and two saturated fatty acids namely palmitic acid (12.0%) and stearic acid (7.2%). The results indicate that T. ferdinandiana kernels have the potential to be utilized as a novel protein source for dietary purposes and non-conventional supply of linoleic, palmitic and oleic acids. PMID:29649154

Submerged Cultivation of Mycelium with High Ergothioneine Content from the Culinary-Medicinal Golden Oyster Mushroom, Pleurotus citrinopileatus (Higher Basidiomycetes).

PubMed

Lin, Shin-Yi; Chien, Shih-Chang; Wang, Sheng-Yang; Mau, Jeng-Leun

2015-01-01

The optimization of submerged culture of the culinary-medicinal golden oyster mushroom, Pleurotus citrinopileatus, was studied using a one-factor-at-a-time, two-stage stimulation and central composite rotatable design to produce mycelia with high ergothioneine content. The optimal culture conditions for mycelia harvested at day 22 were a temperature of 25°C, an inoculation ratio of 5%, 2% glucose, 0.5% yeast extract, and adjustment of the initial pH value to 10. The biomass and ergothioneine content were 8.28 g/L and 10.65 mg/g dry weight (dw), respectively. The addition of an amino acid precursor increased the ergothioneine content of mycelia; cysteine was the most effective. In addition, the results obtained from central composite rotatable design showed that the recommended combination for cysteine, histidine, and methionine was 8, 4, and 0.5 mmol/L, respectively. The predicted ergothioneine content was 13.90 mg/g dw, whereas the experimental maximal ergothioneine content was 14.57 mg/g dw. With the addition of complex precursors and under optimal culture conditions, mycelia harvested at days 16-20 had higher ergothioneine content. Accordingly, the information obtained could be used to produce mycelia with high ergothioneine content.

Mercury concentrations in eggshells of the Southern Ground-Hornbill (Bucorvus leadbeateri) and Wattled Crane (Bugeranus carunculatus) in South Africa.

PubMed

Daso, Adegbenro P; Okonkwo, Jonathan O; Jansen, Raymond; Brandao, José D D O; Kotzé, Antoinette

2015-04-01

In this study, wild hatched eggshells were collected from the nests of threatened Wattled Crane and South Ground-Hornbill in an attempt to determine their total Hg concentrations. A total of fourteen eggshell samples from both bird species were collected from different study areas in the Mpumlanga and KwaZulu-Natal Provinces of South Africa. The eggshells were acid digested under reflux and their total Hg concentrations were determined using cold-vapour atomic absorption spectrophotometry (CV-AAS). The observed total Hg levels for the South Ground-Hornbill samples ranged from 1.31 to 8.88 µg g(-1) dry weight (dw), except for one outlier which had an elevated 75.0 µg g(-1) dw. The levels obtained for the Wattled Crane samples were relatively high and these ranged from 14.84 to 36.37 µg g(-1) dw. Generally, all the measured total Hg concentrations for the Wattled Crane samples exceeded the estimated total Hg levels derived for eggshell which were known to cause adverse reproductive effects in avian species from previous studies. Based on these findings, it is, therefore, possible that the exposure of these birds to elevated Hg may have contributed to their present population decline. Copyright © 2015 Elsevier Inc. All rights reserved.

210Po Activity and concentrations of selected trace elements (As, Cd, Cu, Hg, Pb, Zn) in the muscle tissue of tunas Thunnus albacares and Katsuwonus pelamis from the Eastern Pacific Ocean.

PubMed

Ruelas-Inzunza, Jorge; Soto-Jiménez, Martín Federico; Ruiz-Fernández, Ana Carolina; Bojórquez-Leyva, Humberto; Pérez-Bernal, Hascibe; Páez-Osuna, Federico

2012-12-01

Daily mineral intake (DMI) of Cu and Zn, percentage weekly intake (PWI) of As, Cd, Hg, Pb, and doses of (210)Po were estimated by using their elemental concentration in muscle of two tuna species and the average tuna consumption in Mexico. Skipjack tuna Katsuwonus pelamis had significantly (p < 0.05) higher levels of As (1.38 μg g(-1) dw) and Cu (1.85 μg g(-1) dw) than yellowfin tuna Thunnus albacares, whereas Pb concentrations (0.18 μg g(-1) dw) were significantly (p < 0.05) higher in T. albacares. The sequence of elemental concentrations in both species was Zn > Cu > As > Hg > Pb > Cd. In T. albacares, concentrations of Cd and Pb in muscle tissue were positively correlated (p < 0.05) with weight of specimens, while Cu was negatively correlated. DMI values were below 10 %. PWI figures (<2 %) are not potentially harmful to human health. (210)Po concentration in T. albacares and K. pelamis accounts for 13.5 to 89.7 % of the median individual annual dose (7.1 μSv) from consumption of marine fish and shellfish for the world population.

The excessive enrichment of trace elements in migratory and breeding red-crowned cranes (Grus japonensis) in China.

PubMed

Jinming, Luo; Yongjie, Wang; Zhongyan, Gao; Wenfeng, Wang

2017-07-01

The excessive enrichment of trace elements, such as Pb and Cd, from food may contribute to the decline of migratory red-crowned cranes (Grus japonensis) in China. To test this prediction, we determined the concentrations of Pb and Cd, as well as further macro and trace elements (Ca, Mg, Cu, Zn) in the target species and their prey (sediment, reed root, mollusk, arthropods, and common fish species) in both the wintering (Yancheng wetland) and breeding sites (Zhalong wetland) of cranes in China. The maximum concentrations of Pb (130 mg kg -1 dry weight (dw)) and Cd (10.60 mg kg -1 dw) in the sediments of breeding site and the maximum concentration of Cd (4.50 mg kg -1 dw) in the sediments of wintering site exceeded the probable effect level values (91.30 mg kg -1 for Pb and 3.53 mg kg -1 for Cd), suggesting the potential exposure risk of the examined species. Indeed, Pb and Cd contents of essential foods, i.e., aquatic animals, sampled in two sites were above the limit of allowable concentration recommended by the Joint Food and Agriculture Organization of the United Nations/World Health Organization food standards program. Approximately 80, 31.4, and 60.3 mg kg -1 dw of Pb were detected in the eggshells, liver, and kidney, respectively, of the target species, and the values are above the levels of concern (1.7 mg kg -1 for eggshell and 30 mg kg -1 for liver and kidney) in common birds. Nevertheless, the increased Pb and Cd levels in the prey and bodies of the red-crowned cranes did not induce the levels of Ca and Mg depletion. Average contents of the macronutrients, Ca (1.38 g kg -1 dw) and Mg (1.32 g kg -1 dw), in the liver of the examined species exceeded the background concentrations (0.2-0.4 g kg -1 for Ca and 0.4-0.8 g kg -1 for Mg) in the liver of birds. Consumption of Ca-rich foods, e.g., grits and exoskeleton species, may aid in compensating the possible loss caused by the increased Pb and Cd concentrations in the bodies of the cranes.

Radioactivity, radiological risk and metal pollution assessment in marine sediments from Calabrian selected areas, southern Italy

NASA Astrophysics Data System (ADS)

Caridi, F.; Messina, M.; Faggio, G.; Santangelo, S.; Messina, G.; Belmusto, G.

2018-02-01

The two most significant categories of physical and chemical pollutants in sediments (radionuclides and metals) were investigated in this article, in order to evaluate pollution levels in marine sediments from eight different selected sites of the Calabria region, south of Italy. In particular samples were analyzed to determine natural and anthropic radioactivity and metal concentrations, in order to assess any possible radiological hazard, the level of contamination and the possible anthropogenic impact in the investigated area. Activity concentrations of 226Ra, 232Th, 40K and 137Cs were measured by High Purity Germanium (HPGe) gamma spectrometry. The obtained results show that, for radium (in secular equilibrium with uranium), the specific activity ranges from ( 14 ± 1) Bq/kg dry weight (d.w.) to ( 54 ± 9) Bq/kg d.w.; for thorium, from ( 12 ± 1) Bq/kg d.w. to ( 83 ± 8) Bq/kg d.w.; for potassium, from ( 470 ± 20) Bq/kg d.w. to ( 1000 ± 70) Bq/kg d.w. and for cesium it is lower than the minimum detectable activity value. The absorbed gamma dose rate in air (D), the annual effective dose equivalent (AEDE) outdoor and the external hazard index ( H_ex) were calculated to evaluate any possible radiological risk, mainly due to the use of marine sediments for the beach nourishment. The results show low levels of radioactivity, thus discarding any significant radiological risk. Some metals (As, Cd, Cr tot, Hg, Ni, Pb, Cu, Zn, Mn and Fe), that could be released into the environment by both natural and anthropogenic sources, were investigated through inductively coupled plasma mass spectrometry (ICP-MS) measurements and compared with the limits set by the Italian Legislation, to assess any possible contamination. Experimental results show that they are much lower than the contamination threshold value, thus excluding their presence as pollutants. The degree of sediment contaminations were quantified using enrichment factor ( EF) and geoaccumulation index ( I geo) for some potential hazardous elements. Results show that EF and I geo values of As, Pb and Mn were the greatest among the studied metals. Data of this preliminary study could be helpful in the future to obtain background levels in marine sediments of the investigated region and to develop environmental regulatory frameworks.

Development and application of a method for Cr(III) determination in dairy products by HPLC-ICP-MS.

PubMed

Hernandez, Fanny; Jitaru, Petru; Cormant, Florence; Noël, Laurent; Guérin, Thierry

2018-02-01

This study describes the development of an analytical approach for the determination of Cr(III) in dairy products by microwave assisted extraction, complexation in situ by ethylenediaminetetraacetate (EDTA) and high performance liquid chromatography hyphenated to inductively coupled plasma-mass spectrometry (HPLC-ICP-MS). The extraction step was optimised by using an experimental design. A limit of quantification of 38µgkg -1 dry weight (d.w.) was obtained whereas the bias (%) measured ranged from 10 to 18%. The repeatability and intermediate precision varied between 1.2-5.0% and 7.5-13.5%, respectively. The method was applied to the analysis of several dairy samples beforehand characterized in terms of Cr(VI) and total chromium (Cr total ). Cr(III) concentrations ranged from <13 to 255µgkg -1 d.w. The results showed a good agreement between Cr(III) and Cr total concentration levels. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ethylene promotes mycelial growth and ganoderic acid biosynthesis in Ganoderma lucidum.

PubMed

Zhang, Guang; Ren, Ang; Wu, Fengli; Yu, Hanshou; Shi, Liang; Zhao, Mingwen

2017-02-01

To investigate the effects of ethylene, in the form of ethephon (2-chloroethylphosphonic acid), on mycelial growth and ganoderic acid (GA) accumulation in the higher basidiomycete Ganoderma lucidum. Treatment with both 10 and 15 mM ethephon enhanced the growth of G. lucidum on solid CYM plates and in CYM liquid medium. After optimization using response surface methodology, GA reached 33 mg/g dry cell weight (DW), an increase of 90 %, compared with the control. Lanosterol and squalene contents were 31 and 2.4 μg/g DW, being increased by 1.2- and 0.6-fold, respectively, in response to ethephon. Additionally, the transcriptional levels of hydroxymethylglutaryl-CoA reductase, squalene synthase and oxidosqualene cyclase were up-regulated by 2.6-, 4.3- and 3.8-fold, respectively, compared with the control group. This approach provides an efficient strategy for improving GA accumulation in G. lucidum, with potential future applications.

Metabolic profile of the bioactive compounds of burdock (Arctium lappa) seeds, roots and leaves.

PubMed

Ferracane, Rosalia; Graziani, Giulia; Gallo, Monica; Fogliano, Vincenzo; Ritieni, Alberto

2010-01-20

In this work the bioactive metabolic profile, the antioxidant activity and total phenolic content of burdock (Arctium lappa) seeds, leaves and roots were obtained. TEAC values and total phenolic content for hydro-alcoholic extracts of burdock ranged from 67.39 to 1.63 micromol Trolox equivalent/100g dry weight (DW), and from 2.87 to 45 g of gallic acid equivalent/100g DW, respectively. Phytochemical compounds were analyzed by liquid chromatography coupled to electrospray tandem mass spectrometry (LC/MS/MS) in negative mode. The main compounds of burdock extracts were caffeoylquinic acid derivatives, lignans (mainly arctiin) and various flavonoids. The occurrence of some phenolic acids (caffeic acid, chlorogenic acid and cynarin) in burdock seeds; arctiin, luteolin and quercetin rhamnoside in burdock roots; phenolic acids, quercetin, quercitrin and luteolin in burdock leaves was reported for the first time.

Body weights of newly hatched Anatidae

USGS Publications Warehouse

Smart, M.G.

1965-01-01

As early as 1928 (E.C. Meyers, Auk, 45: 334-388, 1928) investigators realized the importance of bird weights and appealed to ornithologists to record and publish records of these. Practically all of the weights of waterfowl that have been published, however, have been of adults or grown young (see F.H. Kortright, The ducks, geese and swans of North America, Amer. Wildl. Inst., 1943, pp. 381-388; F.C. Bellrose and A.S. Hawkins, Auk, 64: 422-430, 1947; A.L. Neldon and A.C> Martin, J. Wildl. Mgmt., 17: 36-42, 1953; F.A. Hartman, Condor, 57: 221-238, 1955; and D.W. Johnston, Wilson Bull., 75: 437, 1963). The purpose of this paper is to make available a record of weights of a number of species of newly hatched Anatidae.

Effect of a prior bout of preconditioning exercise on muscle damage from downhill walking.

PubMed

Maeo, Sumiaki; Ochi, Yusuke; Yamamoto, Masayoshi; Kanehisa, Hiroaki; Nosaka, Kazunori

2015-03-01

This study investigated whether reduced-duration downhill walking (DW) would confer a protective effect against muscle damage induced by a subsequent bout of longer duration DW performed 1 week or 4 weeks later. Healthy young adults were allocated to a control or one of the preconditioning exercise (PRE-1wk or PRE-4wk) groups (10 men and 4 women per group). PRE-1wk and PRE-4wk groups performed 20-min DW (-28% slope, 5 km/h, 10% body mass added to a backpack) 1 week and 4 weeks before 40-min DW, respectively, and the control group performed 40-min DW only. Maximal voluntary contraction (MVC) knee extension torque, plasma creatine kinase (CK) activity, and muscle soreness (100-mm visual analog scale) were measured before, immediately after, and 24, 48, and 72 h after DW, and the changes in these variables were compared among groups. The control group showed symptoms of muscle damage (e.g., prolonged decrease in MVC: -14% ± 10% at 48 h post-DW) after 40-min DW. Changes in all variables after 40-min DW of PRE-1wk and PRE-4wk groups were 54%-61% smaller (P < 0.05) than the control group, without significant differences between PRE-1wk and PRE-4wk groups for MVC and plasma CK activity. Importantly, changes after the preconditioning exercise (20-min DW) were 67%-69% smaller (P < 0.05) than those after the 40-min DW of the control group. These findings suggest that 20-min DW resulting in minor muscle damage conferred a protective effect against subsequent 40-min DW, and its effect could last for more than 4 weeks.

Distribution of Major Chlorogenic Acids and Related Compounds in Brazilian Green and Toasted Ilex paraguariensis (Maté) Leaves.

PubMed

Lima, Juliana de Paula; Farah, Adriana; King, Benjamin; de Paulis, Tomas; Martin, Peter R

2016-03-23

Ilex paraguariensis (maté) is one of the best sources of chlorogenic acids (CGA) in nature. When leaves are toasted, some isomers are partly transformed into 1,5-γ-quinolactones (CGL). Both CGA and CGL are important contributors to the brew's flavor and are thought to contribute to human health. In this study, we quantified 9 CGA, 2 CGL, and caffeic acid in 20 samples of dried green and toasted maté that are commercially available in Brazil. Total CGA content in green maté varied from 8.7 to 13.2 g/100 g, dry weight (dw). Caffeic acid content varied from 10.8 to 13.5 mg/100 g dw, respectively. Content in toasted maté varied from 1.5 to 4.6 g/100 g and from 1.5 to 7.2 mg/100 g dw, respectively. Overall, caffeoylquinic acid isomers (CQA) were the most abundant CGA in both green and toasted maté, followed by dicaffeoylquinic acids (diCQA) and feruloylquinic acids (FQA). These classes accounted for 58.5%, 40.0%, and 1.5% of CGA, respectively, in green maté and 76.3%, 20.7%, and 3.0%, respectively, in toasted maté. Average contents of 3-caffeoylquinolactone (3-CQL) and 4-caffeoylquinolactone (4-CQL) in commercial toasted samples were 101.5 mg/100 g and 61.8 mg/100 g dw, respectively. These results show that, despite overall losses during the toasting process, CGA concentrations are still substantial in toasted leaves, compared to other food sources of CGA and phenolic compounds in general. In addition to evaluating commercial samples, investigation of changes in CGA profile and formation of 1,5-γ-quinolactones was performed in experimental maté toasting.

Use of ATP to characterize biomass viability in freely suspended and immobilized cell bioreactors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gikas, P.; Livingston, A.G.

1993-12-01

This work describes investigations into the viability of cells growing on 3,4-dichloroaniline (34DCA). Two bio-reactors are employed for microbial growth, a continuous stirred tank (CST) bioreactor with a 2-L working volume, and a three-phase air lift (TPAL) bioreactor with a 3-L working volume. Experiments have been performed at several dilution rates between 0.027 and 0.115 h[sup [minus]1] in the CST bioreactor and between 0.111 and 0.500h[sup [minus]1] in the TPAL bioreactor. The specific ATP concentration was calculated at each dilution rate in the suspended biomass in both bioreactors as well as in the immobilized biomass in the TPAL bioreactor. Themore » cultures were inspected under an electron microscope to monitor compositional changes. Results from the CST bioreactor showed that the biomass-specific ATP concentration increases from 0.44 to 1.86 mg ATP g[sup [minus]1] dry weight (dw) as dilution rate increases from 0.027 to 0.115 h[sup [minus]1]. At this upper dilution rate the cells were washed out. The specific ATP concentration reached a limiting average value of 1.73 mg ATP g[sup [minus]1] dw, which is assumed to be the quantity of ATP in 100% viable biomass, In the TPAL bioreactor, the ATP level increased with dilution rat in both the immobilized and suspended biomass. The specific ATP concentration in the immobilized biomass increased from approximately 0.051 mg ATP g[sup [minus]1] dw at dilution rates between 0.111 and 0.200 h[sup [minus]1] to approximately 0.119 mg ATP g[sup [minus]1] dw at dilution rates between 0.300 and 0.500 h[sup [minus]1].« less

Selenium speciation profiles in biofortified sangiovese wine.

PubMed

Fontanella, Maria Chiara; D'Amato, Roberto; Regni, Luca; Proietti, Primo; Beone, Gian Maria; Businelli, Daniela

2017-09-01

Biofortification is an agronomic-based strategy, utilized by farmers, to produce selenium (Se)-enriched food products that may help reduce dietary deficiencies of Se occurring throughout susceptible regions of the world. The foliar exposure route application ensures a high efficiency of Se assimilation by the plant since it does not depend on root-to-shoot translocation. In this study we treated grapevines of Sangiovese variety in the pre-flowering period with sodium selenate (100mg Se L -1 ). Se content was measured in leaves, fruit at harvest time and in wine respectively in treated and not treated samples with ICP-MS. At harvest, a higher amount of Se in the treated leaves compared to untreated ones was found, 16.0±3.1mgkg -1 dry weight (dw) against 0.17±0.006mgkg -1 dw in the untreated ones. The treated grapes had a content of Se of 0.800±0.08mgkg -1 dw, while that untreated one 0.065±0.025mgkg -1 dw. Immediately after the malolactic fermentation, the wine obtained from treated and untreated vines had a Se content of 0.620±0.09mg Se L -1 and 0.024±0.010mg Se L -1 respectively. In our case the percentage of inorganic Se is 26% of the total Se in the untreated wine, while in Se enriched wine this percentage increase to 47.5% of the total Se. The Se(VI) was the inorganic chemical form more present in enriched wine, probably due to foliar application with selenate. Distributions of Se species suggested being careful to the choice of the enrichment solutions to promote a balanced distribution of different chemical forms, perhaps favouring the accumulation of organic forms. Copyright © 2016 Elsevier GmbH. All rights reserved.

Temporal Trends and Pattern Changes of Short- and Medium-Chain Chlorinated Paraffins in Marine Mammals from the South China Sea over the Past Decade.

PubMed

Zeng, Lixi; Lam, James C W; Wang, Yawei; Jiang, Guibin; Lam, Paul K S

2015-10-06

Temporal trends of short- (SCCPs) and medium-chain chlorinated paraffins (MCCPs) were examined in blubber samples of 50 finless porpoises (Neophocaena phocaenoides) and 25 Indo-Pacific humpback dolphins (Sousa chinensis) collected from the South China Sea between 2004 and 2014. Elevated levels of SCCPs and MCCPs were detected in all blubber samples of both cetacean species. Concentrations of SCCPs ranged from 280 to 3900 ng·g(-1) dry weight (dw) in porpoises and from 430 to 9100 ng·g(-1) dw in dolphins, while concentrations of MCCPs ranged from 320 to 8600 ng·g(-1) dw in porpoises and from 530 to 23 000 ng·g(-1) dw in dolphins. Significantly higher concentrations were present in dolphins than porpoises due to their exposure levels in their living habitats. Strongly linear correlations existed between SCCPs and MCCPs, but there were no significant concentration differences between the genders of the two cetacean species in the same sampling year. Significantly temporal increasing trends of ∑SCCPs and ∑MCCPs have been observed in both porpoise and dolphin samples over the past decade, which reflect the influence of histories of production and usage on the bioaccumulation of CPs in marine mammals in China. An apparent temporal shift trend from SCCPs to MCCPs was also observed in CP accumulation profiles. Complex environmental fractionation from localized sources in the study region via atmospheric transport, oceanic/offshore water transport, and trophic transfer have resulted in different CP accumulation levels and homologue patterns in the two cetacean species. This is the first report of systematic temporal trends of SCCPs and MCCPs in marine mammals.

Spatial distributions and deposition chronology of short chain chlorinated paraffins in marine sediments across the Chinese Bohai and Yellow Seas.

PubMed

Zeng, Lixi; Chen, Ru; Zhao, Zongshan; Wang, Thanh; Gao, Yan; Li, An; Wang, Yawei; Jiang, Guibin; Sun, Liguang

2013-10-15

As the most complex halogenated contaminants, short chain chlorinated paraffins (SCCPs) are scarcely reported in marine environments. In this work, a total of 117 surficial sediment (0-3 cm) samples and two sediment cores were collected from the Chinese Bohai and Yellow Seas to systematically study the spatial and temporal trends of SCCPs at a large scale in the Chinese marine environment. Total SCCP concentrations in the surficial sediments were in the range of 14.5-85.2 ng g(-1) (dry weight, d.w.) with an average level of 38.4 ng g(-1) d.w. Spatial distribution showed a decreasing trend with the distance from the coast to the open waters. Compositional pattern analysis suggested that C10 was the most predominant homologue group, followed by C11, C12, and C13 homologue groups. The concentrations of total SCCPs in sediment cores ranged from 11.6 to 94.7 ng g(-1) d.w. for YS1 and from 14.7 to 195.6 ng g(-1) d.w. for YS2, with sharp rise from the early 1950s to present based on (210)Pb dating technique. The historical records in cores correspond well to the production and usage changes of CPs in China. Multivariate regression statistics indicate TOC, latitude and longitude are the major factors influencing surficial SCCP levels in the Chinese East Seas by combining analysis with the data from the East China Sea (R(2) = 0.332, p < 0.01). These findings indicated that the sources of SCCPs were mainly from river outflows via ocean current and partly from atmospheric depositions by East Asian monsoon in the sampling areas.

Distribution, sources, and air-soil exchange of OCPs, PCBs and PAHs in urban soils of Nepal.

PubMed

Pokhrel, Balram; Gong, Ping; Wang, Xiaoping; Chen, Mengke; Wang, Chuanfei; Gao, Shaopeng

2018-06-01

Due to the high temperature and extensive use of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs), tropical cities could act as secondary sources of these pollutants and therefore received global concern. As compared with other tropical cities, studies on the air-soil exchange of OCPs, PCBs and PAHs in tropical Nepali cities remained limited. In the present study, 39 soil samples from Kathmandu (capital of Nepal) and 21 soil samples from Pokhara (second largest city in Nepal) were collected The soil concentrations of the sum of endosulfans (α- and β-endosulfans) ranged from 0.01 to 16.4 ng/g dw. Meanwhile, ∑dichlorodiphenyltrichloroethane (DDTs) ranged from 0.01 to 6.5 ng/g dw; ∑6PCBs from 0.01 to 9.7 ng/g dw; and ∑15PAHs from 17.1 to 6219 ng/g dw. High concentrations of OCPs were found in the soil of commercial land, while, high soil PAH concentrations were found on tourist/religious and commercial land. Combined the published air concentrations, and the soil data of this study, the directions and fluxes of air-soil exchange were estimated using a fugacity model. It is clear that Nepal is a country contributing prominently to secondary emissions of endosulfans, hexachlorobenzene (HCB), and low molecular weight (LMW) PCBs and PAHs. The flux for all the pollutants in Kathmandu, with ∑endosulfans up to 3553; HCB up to 5263; and ∑LMW-PAHs up to 24378 ng m -2  h -1 , were higher than those in Pokhara. These high flux values indicated the high strength of Nepali soils to act as a source. Copyright © 2018 Elsevier Ltd. All rights reserved.

Phenolic Profiling and Antioxidant Capacity of Eugenia uniflora L. (Pitanga) Samples Collected in Different Uruguayan Locations

PubMed Central

Baenas, Nieves; Gironés-Vilaplana, Amadeo; Cesio, María Verónica; Heinzen, Horacio

2018-01-01

The use of nutrient-rich foods to enhance the wellness, health and lifestyle habits of consumers is globally encouraged. Native fruits are of great interest as they are grown and consumed locally and take part of the ethnobotanic knowledge of the population. Pitanga is an example of a native fruit from Uruguay, consumed as a jelly or an alcoholic beverage. Pitanga has a red-violet pigmentation, which is a common trait for foods that are a good source of antioxidants. Hence, fruits from different Uruguayan regions were analyzed via miniaturized sample preparation method, HPLC-DAD-ESI/MSn and RP-HPLC-DAD techniques to identify and quantify phenolic compounds, respectively. The antioxidant capacity was evaluated via DPPH and ORAC (Oxygen Radical Absorbance Capacity) assays. A multivariate linear regression was applied to correlate the observed antioxidant capacity with the phenolic content. Furthermore, Principal Components Analysis was performed to highlight characteristics between the various samples studied. The main results indicated differences between northern and southern Uruguayan samples. Delphinidin-3-hexoside was present in southern samples (mean of 293.16 µmol/100 g dry weight (DW)) and absent in the sample collected in the north (sample 3). All the samples contain high levels of cyanidin-3-hexoside, but a noticeable difference was found between the northern sample (150.45 µmol/100 g DW) and the southern sample (1121.98 µmol/100 g DW). The antioxidant capacity (mean ORAC of 56370 µmol Trolox®/100 g DW) were high in all the samples compared to the Food and Drug Administration (FDA) database of similar berry-fruits. The results of this study highlight the nutraceutical value of a native fruit that has not been exploited until now. PMID:29695116

Phenolic Profiling and Antioxidant Capacity of Eugenia uniflora L. (Pitanga) Samples Collected in Different Uruguayan Locations.

PubMed

Migues, Ignacio; Baenas, Nieves; Gironés-Vilaplana, Amadeo; Cesio, María Verónica; Heinzen, Horacio; Moreno, Diego A

2018-04-24

The use of nutrient-rich foods to enhance the wellness, health and lifestyle habits of consumers is globally encouraged. Native fruits are of great interest as they are grown and consumed locally and take part of the ethnobotanic knowledge of the population. Pitanga is an example of a native fruit from Uruguay, consumed as a jelly or an alcoholic beverage. Pitanga has a red-violet pigmentation, which is a common trait for foods that are a good source of antioxidants. Hence, fruits from different Uruguayan regions were analyzed via miniaturized sample preparation method, HPLC-DAD-ESI/MS n and RP-HPLC-DAD techniques to identify and quantify phenolic compounds, respectively. The antioxidant capacity was evaluated via DPPH and ORAC (Oxygen Radical Absorbance Capacity) assays. A multivariate linear regression was applied to correlate the observed antioxidant capacity with the phenolic content. Furthermore, Principal Components Analysis was performed to highlight characteristics between the various samples studied. The main results indicated differences between northern and southern Uruguayan samples. Delphinidin-3-hexoside was present in southern samples (mean of 293.16 µmol/100 g dry weight (DW)) and absent in the sample collected in the north (sample 3). All the samples contain high levels of cyanidin-3-hexoside, but a noticeable difference was found between the northern sample (150.45 µmol/100 g DW) and the southern sample (1121.98 µmol/100 g DW). The antioxidant capacity (mean ORAC of 56370 µmol Trolox ® /100 g DW) were high in all the samples compared to the Food and Drug Administration (FDA) database of similar berry-fruits. The results of this study highlight the nutraceutical value of a native fruit that has not been exploited until now.

Geochemistry of mercury in tropical swamps impacted by gold mining.

PubMed

Marrugo-Negrete, José; Pinedo-Hernández, José; Díez, Sergi

2015-09-01

Artisanal and small-scale gold mining (ASGM) poses a serious threat to the local environment. Colombia has very active ASGM activities, where mercury (Hg) ends in piles of mining waste, soils, and waterways. In this study, we assessed Hg speciation and bioavailability in sediments of two tropical swamps, impacted by ASGM. In Ayapel swamp, total Hg (T-Hg) concentrations in sediments ranged between 145 and 313 ng g(-1) dry weight (dw) (mean: 235 ± 49 ng g(-1) dw), whereas Grande Achi swamp levels are 3-fold higher (range: 543-1021 ng g(-1) dw; mean: 722 ± 145 ng g(-1) dw). Even though lower levels of Hg were found in Ayapel, methylation was found to be significantly higher than in Grande Achi, and it is significantly higher in the dry than in the rainy season for both swamps. This increased methylation is linked to the statistically significant correlation between T-Hg, MeHg and organic matter in the Ayapel swamp. In fact, Hg content in both swamps is mainly associated to the organic fraction (Hg-o), with a higher statistically significant difference in Ayapel (43 ± 5%) compared to Grande Achi (33 ± 5%). On the other hand, a significant percentage (30 ± 6%) of elemental Hg fraction (Hg-e) was found in Grande Achi, directly related with Hg released during the gold recovery process from upstream ASGM sites. The percentage of the bioavailable fraction (Hg-w and Hg-h) is elevated (up to 15%), indicating a potential risk to the aquatic environment and human health because these labile Hg species could enter the water column and bioaccumulate in biota. Copyright © 2015 Elsevier Ltd. All rights reserved.

Brominated flame retardants in Korean river sediments, including changes in polybrominated diphenyl ether concentrations between 2006 and 2009.

PubMed

Lee, In-Seok; Kang, Hee-Hyung; Kim, Un-Jung; Oh, Jeong-Eun

2015-05-01

Brominated flame retardants were analyzed in sediment samples from the Nakdong River basin, Korea. The total concentrations of the 27 polybrominated diphenyl ethers (PBDEs), including decabrominated diphenyl ether (BDE 209), analyzed were 0.55-300 ng g(-1) dry weight (dw), the BDE 209 concentrations were 0.39-190 ng g(-1) dw, the tetrabromobisphenol A (TBBPA) concentrations were 0.05-150 ng g(-1) dw, and the total hexabromocyclododecane (sum of α-, β-, γ-HBCDs) concentrations were 0.11-19 ng g(-1) dw. The PBDE and HBCD concentrations were comparable to or lower than the concentrations found in sediments from other countries, whereas the TBBPA concentrations were comparable to or higher than the concentrations found in other countries. The TBBPA concentrations were similar to or lower than the PBDE concentrations, even though more than twice as much TBBPA as total PBDEs is consumed in Korea, and this phenomenon was probably caused by TBBPA and PBDEs being used differently during the manufacture of products, and their different half-lives in sediment and affinities for the particle phase in aquatic environments. Sediment samples from several sampling sites close to facilities where expandable polystyrene, epoxy, and polycarbonate resins are manufactured and handled had relatively high TBBPA and HBCD concentrations. Temporal changes in the PBDE concentration strongly correlated with temporal variations in the geochemical compositions such as total organic carbon content and grain size value of the sediment. The PBDE and HBCD distribution profiles in the sediment samples indicated that commercial PBDE and HBCD products were released locally. Copyright © 2015 Elsevier Ltd. All rights reserved.

Role of pH on antioxidants production by Spirulina (Arthrospira) platensis.

PubMed

Ismaiel, Mostafa Mahmoud Sami; El-Ayouty, Yassin Mahmoud; Piercey-Normore, Michele

2016-01-01

Algae can tolerate a broad range of growing conditions but extreme conditions may lead to the generation of highly dangerous reactive oxygen species (ROS), which may cause the deterioration of cell metabolism and damage cellular components. The antioxidants produced by algae alleviate the harmful effects of ROS. While the enhancement of antioxidant production in blue green algae under stress has been reported, the antioxidant response to changes in pH levels requires further investigation. This study presents the effect of pH changes on the antioxidant activity and productivity of the blue green alga Spirulina (Arthrospira) platensis. The algal dry weight (DW) was greatly enhanced at pH 9.0. The highest content of chlorophyll a and carotenoids (10.6 and 2.4mg/g DW, respectively) was recorded at pH 8.5. The highest phenolic content (12.1mg gallic acid equivalent (GAE)/g DW) was recorded at pH 9.5. The maximum production of total phycobiliprotein (159mg/g DW) was obtained at pH 9.0. The antioxidant activities of radical scavenging activity, reducing power and chelating activity were highest at pH 9.0 with an increase of 567, 250 and 206% compared to the positive control, respectively. Variation in the activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) was also reported. While the high alkaline pH may favor the overproduction of antioxidants, normal cell metabolism and membrane function is unaffected, as shown by growth and chlorophyll content, which suggests that these conditions are suitable for further studies on the harvest of antioxidants from S. platensis. Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

Growing Azolla to produce sustainable protein feed: the effect of differing species and CO2 concentrations on biomass productivity and chemical composition.

PubMed

Brouwer, Paul; Schluepmann, Henriette; Nierop, Klaas Gj; Elderson, Janneke; Bijl, Peter K; van der Meer, Ingrid; de Visser, Willem; Reichart, Gert-Jan; Smeekens, Sjef; van der Werf, Adrie

2018-03-24

Since available arable land is limited and nitrogen fertilizers pollute the environment, cropping systems ought to be developed that do not rely on them. Here we investigate the rapidly growing, N 2 -fixing Azolla/Nostoc symbiosis for its potential productivity and chemical composition to determine its potential as protein feed. In a small production system, cultures of Azolla pinnata and Azolla filiculoides were continuously harvested for over 100 days, yielding an average productivity of 90.0-97.2 kg dry weight (DW) ha -1  d -1 . Under ambient CO 2 levels, N 2 fixation by the fern's cyanobacterial symbionts accounted for all nitrogen in the biomass. Proteins made up 176-208 g kg -1 DW (4.9 × total nitrogen), depending on species and CO 2 treatment, and contained more essential amino acids than protein from soybean. Elevated atmospheric CO 2 concentrations (800 ppm) significantly boosted biomass production by 36-47%, without decreasing protein content. Choice of species and CO 2 concentrations further affected the biomass content of lipids (79-100 g kg -1 DW) and (poly)phenols (21-69 g kg -1 DW). By continuous harvesting, high protein yields can be obtained from Azolla cultures, without the need for nitrogen fertilization. High levels of (poly)phenols likely contribute to limitations in the inclusion rate of Azolla in animal diets and need further investigation. © 2018 The Authors. Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. © 2018 The Authors. Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Occurrence of nonylphenol and nonylphenol monoethoxylate in soil and vegetables from vegetable farms in the Pearl River Delta, South China.

PubMed

Cai, Quan-Ying; Huang, Hui-Juan; Lü, Huixiong; Mo, Ce-Hui; Zhang, Jun; Zeng, Qiao-Yun; Tian, Jun-Jian; Li, Yan-Wen; Wu, Xiao-Lian

2012-07-01

Low molecular-mass nonylphenol ethoxylates (NPEOs) and 4-nonylphenol (NP) are biodegradation products of higher molecular mass NPEOs used as surface active agents, and they are endocrine-disrupting contaminants. In this study, surface soil (0-20 cm) samples and different vegetable samples were collected from 27 representative vegetable farms located in Shenzhen, Dongguan, and Huizhou within the Pearl River Delta region, South China, and NP and nonylphenol monoethoxylate (NP(1)EO) were analyzed using high-performance liquid chromatography with ultraviolet detection. The results show that NP and NP(1)EO were detected in soil and vegetable samples. The concentrations of NP and NP(1)EO in soil samples ranged from nondetectable (ND) to 7.22 μg kg(-1) dry weight (dw) and from ND to 8.24 μg kg(-1) dw, respectively. The average concentrations of both NP and NP(1)EO in soil samples decreased in the following order: Dongguan > Huizhou > Shenzhen. The levels of NP and NP(1)EO in vegetable samples varied from 1.11 to 4.73 μg kg(-1) dw and from 1.32 to 5.33 μg kg(-1) dw, respectively. The greatest levels of both NP and NP(1)EO were observed in water spinach, and the lowest levels of NP and NP(1)EO were recorded in cowpea. The bioconcentration factors (the ratio of contaminant concentration in plant tissue to soil concentration) of NP and NP(1)EO were <1.0 (mean 0.535 and 0.550, respectively). The occurrences of NP and NP(1)EO in this study are compared with other studies, and their potential sources are discussed.

Effect of carbohydrate and protein solutions consumed during a moderate-intensity exercise on post-exercise appetite.

PubMed

Sun, Feng-Hua; Si, Gang-Yan

2017-10-01

This study aimed to investigate whether co-ingestion of carbohydrate and protein during exercise affect the post-exercise ad libitum food intake. Twelve healthy active male participants (mean±SD, age: 20±1; height: 176±6cm; weight: 63.6±5.3kg; VO 2peak : 51.2±7.1ml/kg/min) completed three main experimental trials in a randomized cross-over design. In each trial, the participants completed 1h of ergometer cycling at 60% VO 2peak , followed by 2h recovery. The participants were required to consume one of three solutions every 15min during exercise: distilled water (DW), carbohydrate-electrolyte solution (CE), and carbohydrate-electrolyte-protein solution (CEP). The energy was matched between the two latter solutions. The CHO-to-protein ratio in CEP was 2:1. At the end of recovery period, participants were provided with pizza lunch ad libitum, and the amount consumed was recorded. Several subjective feelings, appetite scores and blood glucose were determined during the experimental trials. No differences were found in either the amount of consumed pizza (DW vs. CE vs. CEP: 607±128 vs. 592±119 vs. 599±125g, P=0.845) or the appetite score before pizza was consumed (DW vs. CE vs. CEP: 14±9 vs. 12±14 vs. 14±10, P=0.357) among the three trials. The blood glucose concentrations during exercise were higher in the CE and CEP trials than in the DW trial. In conclusion, different solutions consumed during a 1h moderate-intensity exercise in the present study did not affect post-exercise appetite. Copyright © 2017 Elsevier Inc. All rights reserved.

Combined toxicity of imidacloprid and three insecticides to the earthworm, Eisenia fetida (Annelida, Oligochaeta).

PubMed

Cang, Tao; Dai, Dejiang; Yang, Guiling; Yu, Yijun; Lv, Lu; Cai, Leiming; Wang, Qiang; Wang, Yanhua

2017-03-01

Although the earthworm Eisenia fetida has been used in many ecotoxicological studies in recent years, most of these studies have only focused on assessing the effects of individual insecticides. In the present study, we aimed to compare the individual and combined toxic effects of imidacloprid and three insecticides (phoxim, chlorpyrifos, and lambda-cyhalothrin) on E. fetida. We showed that imidacloprid had the highest intrinsic toxicity to the worms in filter paper contact test, followed by phoxim and lambda-cyhalothrin, while the least toxicity was found from chlorpyrifos. Moreover, 14-day soil toxicity test revealed that the highest toxicity was still detected for imidacloprid with an LC 50 value of 2.82 (2.61∼3.17) mg a.i. kg -1 dry weight (DW), followed by chlorpyrifos with an LC 50 value of 384.9 (353.5∼440.3) mg a.i. kg -1 DW. Meanwhile, a relatively less toxicity was found for lambda-cyhalothrin with an LC 50 value of 560.3 (475.9∼718.5) mg a.i. kg -1 DW, while the lowest toxicity to E. fetida was observed for phoxim with an LC 50 value of 901.5 (821.3∼1017) mg a.i. kg -1 DW. In addition, significant synergistic responses were found from the ternary mixture of imidacloprid-phoxim-lambda-cyhalothrin and quaternary mixture of imidacloprid-phoxim-chlorpyrifos-lambda-cyhalothrin in both bioassay systems. Therefore, our findings highlighted that the simultaneous presence of several insecticides in the soil environment might lead to increased toxicity, resulting in serious damage to the nontarget organisms compared with individual insecticides.

Birth, growth and death of an antivortex during the propagation of a transverse domain wall in magnetic nanostrips

NASA Astrophysics Data System (ADS)

Yuan, H. Y.; Wang, X. R.

2014-11-01

Antivortex birth, growth and death accompanying the propagation of a transverse domain wall (DW) in magnetic nanostrips are observed and analyzed. Antivortex formation is an intrinsic process of a strawberry-like transverse DW originated from magnetostatic interaction. Under an external magnetic field, the wider width region of a DW tends to move faster than the narrower one. This speed mismatch tilts and elongates DW center line. As a result, an antivortex with a well-defined polarity is periodically born near the tail of the DW center line. The antivortex either moves along the center line and dies on the other side of the nanostrip, or grows to its maximum size, detaches itself from the DW, and vanishes eventually. The former route reverses the polarity of DW while the later keeps the DW polarity unchanged. The evolution of the DW structures is analyzed using winding numbers assigned to each topological defects. The phase diagram in the field-width plane is obtained and the damping constant's influence on the phase diagram is discussed.

Magnetic domain-wall tilting due to domain-wall speed asymmetry

NASA Astrophysics Data System (ADS)

Kim, Dae-Yun; Park, Min-Ho; Park, Yong-Keun; Kim, Joo-Sung; Nam, Yoon-Seok; Hwang, Hyun-Seok; Kim, Duck-Ho; Je, Soong-Geun; Min, Byoung-Chul; Choe, Sug-Bong

2018-04-01

Broken symmetries in diverse systems generate a number of intriguing phenomena and the analysis on such broken symmetries often provides decisive clues for exploring underlying physics in the systems. Recently, in magnetic thin-film systems, the Dzyaloshinskii-Moriya interaction (DMI)—induced by the broken symmetry of structural inversion—accounts for various chiral phenomena, which are of timely issues in spintronics. Here, we report an experimental observation on unexpected tilting of magnetic domain walls (DWs) due to the broken symmetry under the application of the magnetic field transverse to the magnetic wire systems. It has been predicted that the DMI possibly causes such DW tilting in the direction of the energy minimization. However, very interestingly, experimental observation reveals that the DW tilting does not follow the prediction based on the energy minimization, even for the tilting direction. Instead, the DW tilting is governed by the DW speed asymmetry that is initiated by the DW pinning at wire edges. A simple analytic model is proposed in consideration of the DW speed asymmetry at wire edges, which successfully explains the experimental observation of the DW tilting directions and angles, as confirmed by numerical simulation. The present study manifests the decisive role of the DW pinning with the DW speed asymmetry, which determines the DW configuration and consequently, the dynamics.

Comparison between collective coordinate models for domain wall motion in PMA nanostrips in the presence of the Dzyaloshinskii-Moriya interaction

NASA Astrophysics Data System (ADS)

Vandermeulen, J.; Nasseri, S. A.; Van de Wiele, B.; Durin, G.; Van Waeyenberge, B.; Dupré, L.

2018-03-01

Lagrangian-based collective coordinate models for magnetic domain wall (DW) motion rely on an ansatz for the DW profile and a Lagrangian approach to describe the DW motion in terms of a set of time-dependent collective coordinates: the DW position, the DW magnetization angle, the DW width and the DW tilting angle. Another approach was recently used to derive similar equations of motion by averaging the Landau-Lifshitz-Gilbert equation without any ansatz, and identifying the relevant collective coordinates afterwards. In this paper, we use an updated version of the semi-analytical equations to compare the Lagrangian-based collective coordinate models with micromagnetic simulations for field- and STT-driven (spin-transfer torque-driven) DW motion in Pt/CoFe/MgO and Pt/Co/AlOx nanostrips. Through this comparison, we assess the accuracy of the different models, and provide insight into the deviations of the models from simulations. It is found that the lack of terms related to DW asymmetry in the Lagrangian-based collective coordinate models significantly contributes to the discrepancy between the predictions of the most accurate Lagrangian-based model and the micromagnetic simulations in the field-driven case. This is in contrast to the STT-driven case where the DW remains symmetric.

Photosynthesis and Biomass Allocation in Oak Seedlings Grown Under Shade

Treesearch

Shi-Jean S. Sung; Paul P. Kormanik; Stanley J. Zarnoch

1998-01-01

Abstract-Northern red oak (Quercus rubra L.) (NRO) and white oak (Q. alba L.) (WO) acorns were sown into wooden plots and grown under 30 percent shade screen (30 percent S) or 70 percent shade screen (70 percent S). Seedlings grown under full sun were the controls (C). At the end of the first year, the 30 percent S NRO had 30 percent greater seedling dry weight (DW...

Rapid construction of pinhole SPECT system matrices by distance-weighted Gaussian interpolation method combined with geometric parameter estimations

NASA Astrophysics Data System (ADS)

Lee, Ming-Wei; Chen, Yi-Chun

2014-02-01

In pinhole SPECT applied to small-animal studies, it is essential to have an accurate imaging system matrix, called H matrix, for high-spatial-resolution image reconstructions. Generally, an H matrix can be obtained by various methods, such as measurements, simulations or some combinations of both methods. In this study, a distance-weighted Gaussian interpolation method combined with geometric parameter estimations (DW-GIMGPE) is proposed. It utilizes a simplified grid-scan experiment on selected voxels and parameterizes the measured point response functions (PRFs) into 2D Gaussians. The PRFs of missing voxels are interpolated by the relations between the Gaussian coefficients and the geometric parameters of the imaging system with distance-weighting factors. The weighting factors are related to the projected centroids of voxels on the detector plane. A full H matrix is constructed by combining the measured and interpolated PRFs of all voxels. The PRFs estimated by DW-GIMGPE showed similar profiles as the measured PRFs. OSEM reconstructed images of a hot-rod phantom and normal rat myocardium demonstrated the effectiveness of the proposed method. The detectability of a SKE/BKE task on a synthetic spherical test object verified that the constructed H matrix provided comparable detectability to that of the H matrix acquired by a full 3D grid-scan experiment. The reduction in the acquisition time of a full 1.0-mm grid H matrix was about 15.2 and 62.2 times with the simplified grid pattern on 2.0-mm and 4.0-mm grid, respectively. A finer-grid H matrix down to 0.5-mm spacing interpolated by the proposed method would shorten the acquisition time by 8 times, additionally.

PFAAs in Fish and Other Seafood Products from Icelandic Waters

PubMed Central

Halldorsson, Thorhallur I.; Gunnlaugsdottir, Helga

2014-01-01

Perfluorinatedalkyl acids (PFAAs) are of growing concern due to possible health effects on humans. Exposure assessments indicate that fish consumption is one of the major sources of perfluorooctane sulfonate (PFOS) exposure to humans, one of the major PFASs, whereas concerns of overestimation of this exposure source have been raised. Therefore, PFAAs concentrations in fish from the North Atlantic (Icelandic fishing grounds) in the flesh of different fish species were investigated along with more detailed analyses of tissue concentrations in cod (Gadus morhua) and lumpfish (Cyclopterus lumpus). Further, fish feed was investigated as a possible source of PFAAs in aquaculture by examining fish meal as feed ingredient. No PFAAs were detected in the edible part of all fish samples, except for PFOS in pollock (Pollachius virens, 0,05 ng/g wet weight). PFOS was the only PFAA detected in the fish meal samples with the exception of PFOSA in blue whiting (Micromesistius poutassou) meal (0,45 ng/g dry weight (d.w.)), where the PFOS concentration was 1,3–13 ng/g d.w. in the capelin (Mallotus villosus) and mackerel (Scomber scombrus) meal samples. The conclusions of the study are that fish commonly consumed from the Icelandic fishing grounds are unlikely to be an important source of PFAAs exposure. PMID:24782899

Exploring chemical variables in Ligustrum lucidum Ait. F. tricolor (rehd.) Rehd. in relation to air pollutants and environmental conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pignata, M.L.; Canas, M.S.; Carreras, H.A.

1997-09-01

A diagnostic study was done on Ligustrum lucidum Ait. f. tricolor (Rehd.) Rehd. in relation to atmospheric pollutants in Cordoba city, Argentina. The study area receives regional Pollutants and was categorized taking into account traffic level, industrial density, type of industry, location of the sample point in relation to the street corner, treeless condition, and topographic level. Dried weight/fresh weight ratio (DW/FW) and specific leaf area (SLA) were calculated, and concentrations of chlorophylls, carotenoids, total sulfur, soluble proteins, malondialdehyde (MDA), and hydroperoxy conjugated dienes (HPCD) were determined in leaf samples. Sulfur content correlates positively with traffic density and SLA correlatesmore » negatively with some combinations of the categorical variables; MDA correlates positively with topographic level and total protein concentration correlates negatively with treeless condition. On the basis of our results, traffic, location of trees, type of industry, situation of a tree with respect to others, and topographic level are the environmental variables to bear in mind when selecting analogous sampling points in a passive monitoring program. An approximation to predict tree injury may be obtained by measuring DW/FW ratio, proteins, pigments, HPCD, and MDA as they are responsible for the major variability of data.« less

Arsenic in freshwater fish in the Chihuahua County water reservoirs (Mexico).

PubMed

Nevárez, Myrna; Moreno, Myriam Verónica; Sosa, Manuel; Bundschuh, Jochen

2011-01-01

Water reservoirs in Chihuahua County, Mexico, are affected by some punctual and non-punctual geogenic and anthropogenic pollution sources; fish are located at the top of the food chain and are good indicators for the ecosystems pollution. The study goal was to: (i) determine arsenic concentration in fish collected from the Chuviscar, Chihuahua, San Marcos and El Rejon water reservoirs; (ii) to assess if the fishes are suitable for human consumption and (iii) link the arsenic contents in fish with those in sediment and water reported in studies made the same year for these water reservoirs. Sampling was done in summer, fall and winter. The highest arsenic concentration in the species varied through the sampling periods: Channel catfish (Ictalurus punctatus) with 0.22 ± 0.15 mg/kg dw in winter and Green sunfish (Lepomis cyanellus) with 2.00 ± 0.15 mg/kg dw in summer in El Rejon water reservoir. A positive correlation of arsenic contents was found through all sampling seasons in fish samples and the samples of sediment and water. The contribution of the weekly intake of inorganic arsenic, based on the consumption of 0.245 kg fish muscles/body weight/week was found lower than the acceptable weekly intake of 0.015 mg/kg/body weight for inorganic arsenic suggested by FAO/WHO.

Spatial and temporal distribution in density and biomass of two Pseudodiaptomus species (Copepoda: Calanoida) in the Caeté river estuary (Amazon region--North of Brazil).

PubMed

Magalhães, A; Costa, R M; Liang, T H; Pereira, L C C; Ribeiro, M J S

2006-05-01

Spatial and temporal density and biomass distribution of the planktonic copepods Pseudodiaptomus richardi and P. acutus along a salinity gradient were investigated in the Caeté River Estuary (North-Brazil) in June and December, 1998 (dry season) and in February and May, 1999 (rainy season). Copepod biomass was estimated using regression parameters based on the relation of dry weight and body length (prosome) of adult organisms. The Caeté River Estuary was characterized by high spatial and temporal variations in salinity (0.8-37.2). Exponential length-weight relationships were observed for both Pseudodiaptomus species. Density and biomass values oscillated between 0.28-46.18 ind. m-3 and 0.0022-0.3507 mg DW. m-3 for P. richardi; and between 0.01-17.02 ind. m-3 and 0.0005-0.7181 mg DW. m-3 for P. acutus. The results showed that the contribution of P. richardi for the secondary production in the Caeté River Estuary is more important in the limnetic zone than in other zones where euhaline-polyhaline regimes were predominant. However, it was not possible to observe a clear pattern of spatial and temporal distribution for P. acutus.

Occurrence of perchlorate in groundwater, paired farmland soil, lettuce, and rhizosphere soil from Chengdu, China.

PubMed

Tang, Yulu; Zhong, Bifeng; Qu, Bing; Feng, Shujin; Ding, Sanglan; Su, Shijun; Li, Zhi; Gan, Zhiwei

2017-05-24

A total of 28 groundwater, paired farmland soil, lettuce, and its rhizosphere soil samples were collected from Chengdu, China to detect perchlorate levels and to evaluate the relationships of perchlorate concentrations among these matrices. The perchlorate concentrations in the groundwater, farmland soil, lettuce, and rhizosphere soil samples ranged from below detection limit to 60.2 μg L -1 , from below detection limit to 249 μg kg -1 dry weight (dw), from 2.07 to 1010 μg kg -1 wet weight, and from below detection limit to 314 μg kg -1 dw, respectively. Significant correlation was found in the perchlorate levels among the farmland soil, lettuce, and rhizosphere soil, suggesting that they have common pollution sources, or perchlorate might transfer from farmland soil-rhizosphere soil-plant. However, there is no significant correlation between groundwater and the other three matrices, indicating that infiltration from perchlorate contaminated farmland soil was not the predominant source for groundwater pollution in Chengdu. The perchlorate concentrations in the farmland soil and lettuce samples were significantly higher than those in the rhizosphere soil, primarily due to uptake of perchlorate through the rhizosphere micro-environment by lettuce, or accelerated degradation by rhizospheric microorganisms, which contributed more needs further investigation.

Promoting Wound Healing Using Low Molecular Weight Fucoidan in a Full-Thickness Dermal Excision Rat Model

PubMed Central

Park, Jun-Hyeong; Choi, Seong-Hun; Park, Soo-Jin; Lee, Young Joon; Park, Jong Hyun; Song, Phil Hyun; Cho, Chang-Mo; Ku, Sae-Kwang; Song, Chang-Hyun

2017-01-01

Low molecular weight fucoidan (LMF) has been reported to possess anti-inflammatory and antioxidant activities. Thus, we examined the effects of LMF extracted from Undaria pinnatifida on dermal wounds. Five round dermal wounds were created on the dorsal back of rats, and they were then treated topically with distilled water (DW), Madecasol Care™ (MC) or LMF at 200, 100 and 50 mg/mL, twice a day for a week. There were dose-dependent increases in wound contraction in the groups receiving LMF but not in the MC group, compared with the DW. Histopathological examination revealed that LMF treatment accelerated wound healing, which was supported by increases in granular tissue formation on day four post-treatment but a decrease on day seven, accompanied by an evident reduction in inflammatory cells. In the LMF-treated wounds, collagen distribution and angiogenesis were increased in the granular tissue on days four and seven post-treatment. Immunoreactive cells for transforming growth factor-β1, vascular endothelial growth factor receptor-2 or matrix metalloproteinases 9 were also increased, probably due to tissue remodeling. Furthermore, LMF treatment reduced lipid peroxidation and increased antioxidant activities. These suggested that LMF promotes dermal wound healing via complex and coordinated antioxidant, anti-inflammatory and growth factor-dependent activities. PMID:28387729

Diffusion measurements in the ischemic human brain with a steady-state sequence.

PubMed

Brüning, R; Wu, R H; Deimling, M; Porn, U; Haberl, R L; Reiser, M

1996-11-01

The authors evaluate the clinical usefulness of a diffusion-weighted steady-state free-precession (SSFP) sequence to detect acute and subacute ischemic changes. Twenty-four patients were examined on a 1.5-tesla scanner, using a SSFP-sequence (repetition time [TR]/ echo time [TE] = 22/3-8 mseconds). The slice thickness was 5 mm, 10 averages, 57 seconds per slice. The diffusion gradient strength was 23 millitesla/m, with b-values from 165 to 598 seconds/mm2. Diffusion-weighted images (DWI) were compared with T2-weighted images. The diffusion-weighted SSFP sequence produced diagnostic quality images in 23 of 24 patients. Diffusion depicted (group 1: 0-12 hours) more acute lesions (3 of 6) than T2-weighted images (2 of 6); the mean lesion diameter depicted by diffusion was 10.9 mm (standard deviation [SD], 12.3) and in T2-weighted images was 4.7 mm (SD 6.8). A significant correlation (P < 0.017) in subacute lesions was found when diffusion was compared with turbo spin echo (mean size difference/T2 = 18.5/17.5 mm, SD 13.2/12.2). The diffusion-weighted SSFP-sequence is more sensitive in acute ischemia and delineates likewise in subacute ischemia, when compared with T2-weighted imaging.

Importance of relationship quality in the success of data warehouse systems

NASA Astrophysics Data System (ADS)

Almabhouh, Alaaeddin; Saleh, Abdul; Ahmad, Azizah

2011-10-01

Increased organizational dependence on data warehouse (DW) systems drives management attention towards improving DW systems success. However, the successful implementation rate of DW systems is low and many firms did not achieve intended goals. A recent studies show that improves and evaluates DW success is one of the top concerns facing IT/DW executives. Existing information system (IS) research has studied DW success more from information quality and system quality. Researchers argue in this study that we should also take the relationship quality, which has significant research and practical implications in that it connects to IS success directly. As our first attempt, this study, referring to both IS and marketing literature, examines how communication, coordination, cooperation, commitment, and trust can be achieved to some degrees by high quality relationships between DW parties.

Spatial and temporal distributions of hexabromocyclododecanes in the vicinity of an expanded polystyrene material manufacturing plant in Tianjin, China.

PubMed

Zhu, Hongkai; Zhang, Kai; Sun, Hongwen; Wang, Fei; Yao, Yiming

2017-03-01

To investigate the environmental fate of 3 main hexabromocyclododecane diastereoisomers (α-, β-, and γ-HBCDs), samples from various environmental media, including outdoor settled dust, soil, sediment, plant tissues (holly, cypress and pine) and marine species (shrimp, crab and fish) were obtained around an expanded polystyrene material manufacturing plant in Tianjin, China. The 3 main HBCD diastereoisomers were detected with the total concentrations ranging from 328 to 31,752 ng/g dry weight (dw), 2.91-1730 ng/g dw, 23.5-716 ng/g dw, 3.45-2494 ng/g dw, and 0.878-44.8 ng/g dw in the dust, soil, sediment, plant tissues, and marine species, respectively. This indicated that a point source of HBCDs could bring wide impact on its vicinal environment. A significant increasing trend of HBCDs concentrations was noted, as indicated by 12.9-41.6% of increasing rates in total concentrations of HBCDs at four sediment sites in the past five years. The diastereoisomer profiles were sorted into 3 groups: dust, soil and sediment, which had no statistical difference from commercial EPS-products (p > 0.05); plant tissues, which showed a moderate increase of α-isomer (22.9 ± 3.3%); and marine species, which were dominated by α-isomer (62.6 ± 2.8%). For α- and β-isomers, the results of enantiomeric analysis showed a preferential accumulation of the (+)-enantiomer in part of plant tissues and all marine organisms (p < 0.05). However, there was no enantioselectivity of the 3 isomers in dust, soil, and sediment samples (p > 0.05). Besides, marine food web magnification is observed for HBCDs, with trophic magnification factors close to 2. The daily intakes of HBCDs were estimated to be 0.058-5.84 ng/kg-bw/day for local residents through dust and soil ingestion and 0.048-8.43 ng/kg-bw/day for Tianjin citizens through seafood consumption. Copyright © 2016 Elsevier Ltd. All rights reserved.

Technique of diffusion weighted imaging and its application in stroke

NASA Astrophysics Data System (ADS)

Li, Enzhong; Tian, Jie; Han, Ying; Wang, Huifang; Li, Wu; He, Huiguang

2003-05-01

To study the application of diffusion weighted imaging and image post processing in the diagnosis of stroke, especially in acute stroke, 205 patients were examined by 1.5 T or 1.0 T MRI scanner and the images such as T1, T2 and diffusion weighted images were obtained. Image post processing was done with "3D Med System" developed by our lab to analyze data and acquire the apparent diffusion coefficient (ADC) map. In acute and subacute stage of stroke, the signal in cerebral infarction areas changed to hyperintensity in T2- and diffusion-weighted images, normal or hypointensity in T1-weighted images. In hyperacute stage, however, the signal was hyperintense just in the diffusion weighted imaes; others were normal. In the chronic stage, the signal in T1- and diffusion-weighted imaging showed hypointensity and hyperintensity in T2 weighted imaging. Because ADC declined obviously in acute and subacute stage of stroke, the lesion area was hypointensity in ADC map. With the development of the disease, ADC gradually recovered and then changed to hyperintensity in ADC map in chronic stage. Using diffusion weighted imaging and ADC mapping can make a diagnosis of stroke, especially in the hyperacute stage of stroke, and can differentiate acute and chronic stroke.

Oscillatory dependence of current driven domain wall motion on current pulse length

NASA Astrophysics Data System (ADS)

Thomas, Luc

2007-03-01

The motion of domain walls (DW) in magnetic nanowires driven by spin torque from spin-polarized current is of considerable interest. Most previous work has considered the effect of dc or ˜microsecond long current pulses. Here, we show that the dynamics of DWs driven by nanosecond-long current pulses is unexpectedly complex. In particular, we show that the current driven motion of a DW, confined to a pinning site in a permalloy nanowire, exhibits an oscillatory dependence on the current pulse length with a period of just a few nanoseconds [1]. This behavior can be understood within a surprisingly straightforward one dimensional analytical model of the DW's motion. When a current pulse is applied, the DW's position oscillates within the pinning potential out of phase with the DW's out-of-plane magnetization, where the latter acts like the DW's momentum. Thus, the current driven motion of the DW is akin to a harmonic oscillator, whose frequency is determined by the ``mass'' of the DW and where the restoring force is related to the slope of the pinning potential. Remarkably, when the current pulse is turned off during phases of the DW motion when it has enough momentum, the amplitude of the oscillations can be amplified such that the DW exits the pinning potential well after the pulse is turned off. This oscillatory depinning occurs for currents smaller than the dc threshold current, and, moreover, the DW moves against the electron flow, opposite to the propagation direction above the dc threshold. These effects can be further amplified by using trains of current pulses whose lengths and separations are matched to the DW's oscillation period. In this way, we have demonstrated a five fold reduction in the threshold current required to move a DW out of a pinning site, making this effect potentially important for technological applications. [1] L. Thomas, M. Hayashi, X. Jiang, R. Moriya, C. Rettner and S.S.P. Parkin, Nature 443, 197 (2006).

Notch-Boosted Domain Wall Propagation in Magnetic Nanowires

NASA Astrophysics Data System (ADS)

Wang, Xiang Rong; Yuan, Hauiyang

Magnetic domain wall (DW) motion along a nanowire underpins many proposals of spintronic devices. High DW propagation velocity is obviously important because it determines the device speed. Thus it is interesting to search for effective control knobs of DW dynamics. We report a counter-intuitive finding that notches in an otherwise homogeneous magnetic nanowire can boost current-induced domain wall (DW) propagation. DW motion in notch-modulated wires can be classified into three phases: 1) A DW is pinned around a notch when the current density is below the depinning current density. 2) DW propagation velocity above the depinning current density is boosted by notches when non-adiabatic spin-transfer torque strength is smaller than the Gilbert damping constant. The boost can be many-fold. 3) DW propagation velocity is hindered when non-adiabatic spin-transfer torque strength is larger than the Gilbert damping constant. This work was supported by Hong Kong GRF Grants (Nos. 163011151 and 605413) and the Grant from NNSF of China (No. 11374249).

Apparent diffusion coefficients in prostate cancer: correlation with molecular markers Ki-67, HIF-1α and VEGF.

PubMed

Ma, Teng; Yang, Shaolin; Jing, Haiyan; Cong, Lin; Cao, Zhixin; Liu, Zhiling; Huang, Zhaoqin

2018-03-01

Prostate cancer (PCa) is the second most common cancer in men. The Gleason score (GS) and biomarkers play important roles in the diagnosis and treatment of patients with PCa. The purpose of this study was to investigate the relationship between the apparent diffusion coefficient (ADC) and the molecular markers Ki-67, hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) in PCa. Thirty-nine patients with 39 lesions, who had been diagnosed with PCa, were enrolled in this study. All patients underwent diffusion-weighted magnetic resonance imaging (DW-MRI) (b = 800 s/mm 2 ). The expression of Ki-67, HIF-1α and VEGF was assessed by immunohistochemistry. Statistical analysis was applied to analyze the association between ADC and prostate-specific antigen (PSA), GS and the expression of Ki-67, HIF-1α and VEGF. The group differences in ADC among different grades of Ki-67, HIF-1α and VEGF were also analyzed. The mean ± standard deviation of ADC was (0.76 ± 0.27) × 10 -3  mm 2 /s. ADC correlated negatively with PSA and GS (p < 0.05). The Ki-67 staining index (SI), HIF-1α expression and VEGF expression in PCa were correlated inversely with ADC, controlling for age (r = -0.332, p < 0.05; r = -0.662, p < 0.0005; and r = -0.714, p < 0.0005, respectively). ADC showed a significant difference among different grades of Ki-67 (F = 9.164, p = 0.005), HIF-1α (F = 40.333, p < 0.0005) and VEGF (F = 22.048, p < 0.0005). In conclusion, ADC was correlated with PSA, GS, and Ki-67, HIF-1α and VEGF expression in patients with PCa. ADC may be used to evaluate tumor proliferation, hypoxia and angiogenesis in PCa. Copyright © 2018 John Wiley & Sons, Ltd.

Concentrations of metals in blood and feathers of nestling ospreys (Pandion haliaetus) in Chesapeake and Delaware Bays

USGS Publications Warehouse

Rattner, B.A.; Golden, N.H.; Toschik, P.C.; McGowan, P.C.; Custer, T.W.

2008-01-01

In 2000, 2001, and 2002, blood and feather samples were collected from 40-45-day-old nestling ospreys (Pandion haliaetus) from Chesapeake Bay and Delaware Bay and River. Concentrations of 18 metals, metalloids, and other elements were determined in these samples by inductively coupled plasma-mass spectroscopy, and Hg concentrations were measured by cold vapor atomic absorption spectroscopy. When compared to concurrent reference areas (South, West, and Rhode Rivers), mean As and Hg concentrations in blood were greater (p < 0.05) in two of three Chesapeake Bay regions of concern (Baltimore Harbor [As: 1.18 vs. 0.548 mug/g dw], Anacostia River [Hg: 0.305 vs. 0.178 mug/g dw], and Elizabeth River [As: 0.876 vs. 0.663 mug/g dw; Hg: 0.260 vs. 0.180 mug/g dw]). Lead was detected more frequently in blood of nestlings from the highly industrialized Elizabeth River compared to the rural reference area. When compared to the concurrent reference area, mean Al, Ba, Hg, Mn, and Pb concentrations in feathers were substantially greater (p < 0.05) in one or more Chesapeake regions of concern (Anacostia River [Al: 206 vs. 62.1 mug/g dw; Ba: 3.31 vs. 0.823 mug/g dw; Mn: 65.4 vs. 22.9 mug/g dw] and Elizabeth River [Al: 165 vs. 63.5 mug/g dw; Hg: 1.24 vs. 0.599 mug/g dw; Pb 1.47 vs. 0.543 mug/g dw]). When compared to the coastal Inland Bays reference area, feathers of nestlings from northern Delaware Bay and River had greater concentrations (p < 0.05) of Ba (1.90 vs. 0.660 mug/g dw), Fe (258 vs. 109 mug/g dw), Mn (18.5 vs. 4.66 mug/g dw), Mo (0.130 vs. 0.040 mug/g dw), Pb (1.96 vs. 0.624 mug/g dw), and V (0.671 vs. 0.325 mug/g dw), presumably due to extensive metal-working and petroleum refinery activities. Concentrations of Hg in nestling feathers from Delaware were frequently greater than in the Chesapeake. The present findings and those of related reproductive studies suggest that concentrations of several heavy metals (e.g., Cd, Hg, Pb) in nestling blood and feathers from Chesapeake and Delaware Bays were below toxicity thresholds and do not seem to be affecting chick survival during the nestling period.

Micrococcus lactis sp. nov., isolated from dairy industry waste.

PubMed

Chittpurna; Singh, Pradip K; Verma, Dipti; Pinnaka, Anil Kumar; Mayilraj, Shanmugam; Korpole, Suresh

2011-12-01

A Gram-positive, yellow-pigmented, actinobacterial strain, DW152(T), was isolated from a dairy industry effluent treatment plant. 16S rRNA gene sequence analysis indicated that strain DW152(T) exhibited low similarity with many species with validly published names belonging to the genera Micrococcus and Arthrobacter. However, phenotypic properties including chemotaxonomic markers affiliated strain DW152(T) to the genus Micrococcus. Strain DW152(T) had ai-C(15:0) and i-C(15:0) as major cellular fatty acids, and MK-8(H(2)) as the major menaquinone. The cell-wall peptidoglycan of strain DW152(T) had l-lysine as the diagnostic amino acid and the type was A4α. The DNA G+C content of strain DW152(T) was 68.0 mol%. In 16S rRNA gene sequence analysis, strain DW152(T) exhibited significant similarity with Micrococcus terreus NBRC 104258(T), but the mean value of DNA-DNA relatedness between these strains was only 42.3%. Moreover, strain DW152(T) differed in biochemical and chemotaxonomic characteristics from M. terreus and other species of the genus Micrococcus. Based on the above differences, we conclude that strain DW152(T) should be treated as a novel species of the genus Micrococcus, for which the name Micrococcus lactis sp. nov. is proposed. The type strain of Micrococcus lactis sp. nov. is DW152(T) (=MTCC10523(T) =DSM 23694(T)).

Benthic cyanobacteria: A source of cylindrospermopsin and microcystin in Australian drinking water reservoirs.

PubMed

Gaget, Virginie; Humpage, Andrew R; Huang, Qiong; Monis, Paul; Brookes, Justin D

2017-11-01

Cyanobacteria represent a health hazard worldwide due to their production of a range of highly potent toxins in diverse aquatic environments. While planktonic species have been the subject of many investigations in terms of risk assessment, little is known about benthic forms and their impact on water quality or human and animal health. This study aimed to purify isolates from environmental benthic biofilms sampled from three different drinking water reservoirs and to assess their toxin production by using the following methods: Enzyme-Linked Immunosorbent Assay (ELISA), High-Performance Liquid Chromatography (HPLC), Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) and quantitative PCR (qPCR). Microscopic observation of the isolates allowed the identification of various filamentous cyanobacterial genera: Anabaena (benthic form), Calothrix and Nostoc from the Nostocales and Geitlerinema, Leptolyngbya, Limnothrix, Lyngbya, Oxynema, Phormidium and Pseudanabaena representing non-heterocystous filamentous cyanobacteria. The Phormidium ambiguum strain AWQC-PHO021 was found to produce 739 ng/mg of dry weight (d/w) of cylindrospermopsin and 107 ng/mg (d/w) of deoxy-cylindrospermopsin. The Nostoc linckia strain AWQC-NOS001 produced 400 ng/mg (d/w) of a microcystin analogue. This is the first report of hepatotoxin production by benthic cyanobacteria in temperate Australian drinking water reservoirs. These findings indicate that water quality monitoring programs need to consider benthic cyanobacteria as a potential source of toxins. Copyright © 2017 Elsevier Ltd. All rights reserved.

Cr localization and speciation in roots of chromate fed Helianthus annuus L. seedlings using synchrotron techniques.

PubMed

de la Rosa, Guadalupe; Castillo-Michel, Hiram; Cruz-Jiménez, Gustavo; Bernal-Alvarado, Jesús; Córdova-Fraga, Teodoro; López-Moreno, Laura; Cotte, Marine

2014-01-01

In order to gain knowledge on the potential use of Helianthus annuus L. for the remediation of Cr(VI) polluted waters, hydroponics experiments were set up to determine Cr uptake and tolerance in different Cr(VI)-sulfate conditions, and Cr biotransformations. Results indicated that Cr(VI) promoted seed germination, and plant tolerance was higher at younger plant stages. Cr uptake was dependent on sulfate concentrations. The highest Cr levels in roots and shoots (13,700 and 2,500 mg kg(-1) dry weight (DW), respectively) were obtained in 1 mM sulfate. The lowest Cr uptake in roots (10,600 mg kg(-1) DW) was observed in seedlings treated with no sulfate. In shoots, Cr concentration was of 1,500 mg kg(-1)DW for the 1 mM sulfate treatment, indicating a different level of interaction between chromate and sulfate in both tissues. For the first time, using micro X-ray florescence (muXRF), we demonstrated Cr reaches the root stele and is located in the walls of xylem vessels. Bulk and micro X-ray Absorption Near-Edge Structure (muXANES) results showed that Cr in the roots is mostly in the form of Cr(III) phosphate (80%), with the remainder complexed to organic acids. Our results suggest this plant species may serve for Cr(VI) rhizofiltration purposes.

Mercury speciation in brain tissue of polar bears (Ursus maritimus) from the Canadian Arctic.

PubMed

Krey, Anke; Kwan, Michael; Chan, Hing Man

2012-04-01

Methylmercury (MeHg) is a neurotoxicant that has been found at elevated concentrations in the Arctic ecosystem. Little is known about its internal dose in wildlife such as polar bears. We measured concentrations of mercury (Hg) in three different brain regions (cerebellum, frontal lobe and brain stem) of 24 polar bears collected from the Nunavik, Canada between 2000 and 2003. Speciation of Hg was measured by High Performance Liquid Chromatography coupled to Inductively Coupled Plasma Mass Spectroscopy (HPLC-ICP-MS). Concentrations of mean total Hg in brain tissue were up to 625 times lower (0.28 ± 0.07 mg kg(-1) dry weight (dw) in frontal lobe, 0.23 ± 0.07 mg kg(-1) dw in cerebellum and 0.12 ± 0.0 3mg kg(-1) dw in brain stem) than the mean total Hg concentration previously reported in polar bear liver collected from Eastern Baffin Island. Methylmercury (MeHg) accounted for 100% of the Hg found in all three brain regions analyzed. These results suggest that polar bear might reduce the toxic effects of Hg by limiting the uptake into the brain and/or decrease the rate of demethylation so that Hg can be excreted from the brain more easily. The toxicokinetics and the blood-brain-barrier mechanisms of polar bears are still unknown and further research is required. Copyright © 2012 Elsevier Inc. All rights reserved.

Distribution of pesticides and PCBs in sediments of agricultural drains in the Culiacan Valley, Sinaloa, Mexico.

PubMed

García-de la Parra, Luz María; Cervantes-Mojica, L Juleny; González-Valdivia, Carolina; Martínez-Cordero, Francisco J; Aguilar-Zárate, Gabriela; Bastidas-Bastidas, Pedro; Betancourt-Lozano, Miguel

2012-10-01

Agriculture is one of the most important economic activities in Sinaloa, Mexico. The Culiacan Valley is an extensive agricultural region characterized by a variety of crops with high-yield productions. In this study, concentrations of organochlorine (OCPs) and organophosphorus (OPs) pesticides and polychlorobiphenyls (PCBs) were determined in sediments of the agricultural drainage system of Culiacan Valley. Overall, 32 compounds were detected, with concentrations widely ranging from 0.03 to 1 294 ng g(-1) dry weight. OCP concentrations (15) ranged from 0.1 to 20.19 ng g(-1) dw. OP concentrations (8) ranged from 0.03 to 1294 ng g(-1) dw, and diazinon was the compound with the highest concentration. PCB concentrations were also determined and varied from 0.05 to 3.29 ng g(-1) dw. Other compounds detected included permethrin, triadimefon, and fipronil. The central zone registered the higher concentrations and the greatest number of compounds, which could be related to the occurrence of horticultural fields in this zone. According to sediment quality guidelines, the compounds exceeding the probable effect level were γ-HCH, p,p'-DDT and p,p'-DDE, while the pesticides above the maximum permissible concentration were endosulfan, azinphos methyl, diazinon, dichlorvos, and permethrin. Although Sinaloa is an important agricultural crop producer in northwest Mexico, there are not many studies dealing with pesticide distribution in agricultural areas.

Neuroprotective Effects of Korean Red Pine(Pinus densiflora) Bark Extract and Its Phenolics.

PubMed

Kim, Ji-Won; Im, Sungbin; Jeong, Ha-Ram; Jung, Young-Seung; Lee, Inil; Kim, Kwan Joong; Park, Seung Kook; Kim, Dae-Ok

2018-03-15

Korean red pine ( Pinus densiflora ) is one of the major Pinus species in Korea. Red pine barkis removed prior to the chipping process in the wood industry and discarded aswaste. However, red pine bark contains a considerable amount of naturally occurring phenolics including flavonoids and therefore may have a variety of biological effects. In this study, we investigated if Korean red pine bark extract (KRPBE) could protect neuronal PC-12 cells from oxidative stress and inhibit cholinesterase activity.Analysis of reversed-phase high-performance liquid chromatography results revealed four phenolics in KRPBE:vanillin, protocatechuic acid, catechin and taxifolin.Total phenolic and flavonoid contents of KRPBE were 397.9 mg gallic acid equivalents/g dry weight (DW) and 248.7 mg catechin equivalents/g DW, respectively. Antioxidant capacities of KRPBE measured using ABTS, DPPH, and ORAC assays were 697.3, 521.8, and 2,627.7 mg vitamin C equivalents/g DW, respectively. KRPBE and its identified phenolics protected against H 2 O 2 -induced oxidative cell death in a dose-dependent manner. Acetylcholinesterase and butyrylcholinesterase, which degrade the neurotransmitter acetylcholine to terminate neurotransmission in synaptic clefts, were inhibited by treatment with KRPBE and its identified phenolics. Taken together, these results suggest that KRPBE and its constituent antioxidative phenolics are potent neuroprotective agents that can maintain cell viability in the context of oxidative stress and inhibit cholinesterase activity.

Exploratory data analysis of acceleration signals to select light-weight and accurate features for real-time activity recognition on smartphones.

PubMed

Khan, Adil Mehmood; Siddiqi, Muhammad Hameed; Lee, Seok-Won

2013-09-27

Smartphone-based activity recognition (SP-AR) recognizes users' activities using the embedded accelerometer sensor. Only a small number of previous works can be classified as online systems, i.e., the whole process (pre-processing, feature extraction, and classification) is performed on the device. Most of these online systems use either a high sampling rate (SR) or long data-window (DW) to achieve high accuracy, resulting in short battery life or delayed system response, respectively. This paper introduces a real-time/online SP-AR system that solves this problem. Exploratory data analysis was performed on acceleration signals of 6 activities, collected from 30 subjects, to show that these signals are generated by an autoregressive (AR) process, and an accurate AR-model in this case can be built using a low SR (20 Hz) and a small DW (3 s). The high within class variance resulting from placing the phone at different positions was reduced using kernel discriminant analysis to achieve position-independent recognition. Neural networks were used as classifiers. Unlike previous works, true subject-independent evaluation was performed, where 10 new subjects evaluated the system at their homes for 1 week. The results show that our features outperformed three commonly used features by 40% in terms of accuracy for the given SR and DW.

Polybrominated diphenyl ether flame retardant concentrations in faeces from young children in Queensland, Australia and associations with environmental and behavioural factors.

PubMed

English, Karin; Chen, Yiqin; Toms, Leisa-Maree; Jagals, Paul; Ware, Robert S; Mueller, Jochen F; Sly, Peter D

2017-10-01

The aim of our study was to investigate children's exposure to the flame retardants polybrominated diphenyl ethers (PBDEs) by analysing faecal content, a non-invasive matrix, as well as responses to an exposure-assessment questionnaire. A convenience sample of 61 parents with children (aged >3 months to <2 years) completed an online pre-tested questionnaire and provided faecal samples for analysis by high resolution gas chromatography/mass spectrometry. BDE-209 was the dominant congener in faecal samples adjusted to 8.3ng/g dry weight (dw), with >80% samples above the limit of detection (LOD). BDE-47 (0.23ng/g dw) and BDE-153 (0.03ng/g dw) were each detected above the LOD in approximately 60% of samples. Age was associated with BDE-47 (-7%/month) and BDE-153 (-12%/month) concentrations in faeces, but not BDE-209. Other variables associated with PBDE concentrations included features of the home (carpet, pets) and behaviour (hand-to-mouth, removing shoes, using a car sunshade, frequency of walks outdoors). However, given the small sample size of this study additional research is required to confirm these findings. In this study we demonstrated that faeces may be a viable alternative to monitor human exposure to PBDEs, but further validation studies are required. Copyright © 2017. Published by Elsevier Inc.

Mercury in fruiting bodies of dark honey fungus (Armillaria solidipes) and beneath substratum soils collected from spatially distant areas.

PubMed

Falandysz, Jerzy; Mazur, Aneta; Kojta, Anna K; Jarzyńska, Grażyna; Drewnowska, Małgorzata; Dryżałowska, Anna; Nnorom, Innocent C

2013-03-15

This paper reports data on bioconcentration potential and baseline mercury concentrations of fruiting bodies of dark honey fungus (Armillaria solidipes) Peck and soil substrate layer (0-10 cm) from 12 spatially distant sites across Poland. Mercury content of caps, stipes and soil samples were determined using validated analytical procedure including cold-vapor atomic absorption spectroscopy after thermal decomposition of the sample matrix and further amalgamation and desorption of mercury from gold wool. Mean mercury concentrations ranged from 20 ± 8 to 300 ± 70 ng g(-1) dry weight (dw) in caps, from 20 ± 6 to 160 ± 40 ng g(-1) dw in stipes, and in underlying soil were from 20 ± 2 to 100 ± 130 ng g(-1) dw. The results showed that stipes mercury concentrations were 1.1- to 1.7-fold lower than those of caps. All caps and the majority of stipes were characterized by bioconcentration factor values > 1, indicating that dark honey fungus can be characterized as a moderate mercury accumulator. Occasional or relatively frequent eating of meals including caps of dark honey fungus is considered safe in view of the low total mercury content, and the mercury intake rates are below the current reference dose and provisionally tolerable weekly intake limits for this hazardous metal. © 2012 Society of Chemical Industry.

Organic and inorganic nitrogen uptake by 21 dominant tree species in temperate and tropical forests.

PubMed

Liu, Min; Li, Changcheng; Xu, Xingliang; Wanek, Wolfgang; Jiang, Ning; Wang, Huimin; Yang, Xiaodong

2017-11-01

Evidence shows that many tree species can take up organic nitrogen (N) in the form of free amino acids from soils, but few studies have been conducted to compare organic and inorganic N uptake patterns in temperate and tropical tree species in relation to mycorrhizal status and successional state. We labeled intact tree roots by brief 15N exposures using field hydroponic experiments in a temperate forest and a tropical forest in China. A total of 21 dominant tree species were investigated, 8 in the temperate forest and 13 in the tropical forest. All investigated tree species showed highest uptake rates for NH4+ (ammonium), followed by glycine and NO3- (nitrate). Uptake of NH4+ by temperate trees averaged 12.8 μg N g-1 dry weight (d.w.) root h-1, while those by tropical trees averaged 6.8 μg N g-1 d.w. root h-1. Glycine uptake rates averaged 3.1 μg N g-1 d.w. root h-1 for temperate trees and 2.4 μg N g-1 d.w. root h-1 for tropical trees. NO3- uptake was the lowest (averaging 0.8 μg N g-1 d.w. root h-1 for temperate trees and 1.2 μg N g-1 d.w. root h-1 for tropical trees). Uptake of NH4+ accounted for 76% of the total uptake of all three N forms in the temperate forest and 64% in the tropical forest. Temperate tree species had similar glycine uptake rates as tropical trees, with the contribution being slightly lower (20% in the temperate forest and 23% in the tropical forest). All tree species investigated in the temperate forest were ectomycorrhizal and all species but one in the tropical forest were arbuscular mycorrhizal (AM). Ectomycorrhizal trees showed significantly higher NH4+ and lower NO3- uptake rates than AM trees. Mycorrhizal colonization rates significantly affected uptake rates and contributions of NO3- or NH4+, but depended on forest types. We conclude that tree species in both temperate and tropical forests preferred to take up NH4+, with organic N as the second most important N source. These findings suggest that temperate and tropical forests demonstrate similar N uptake patterns although they differ in physiology of trees and soil biogeochemical processes. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Enhanced daidzin production from jasmonic and acetyl salicylic acid elicited hairy root cultures of Psoralea corylifolia L. (Fabaceae).

PubMed

Zaheer, Mohd; Reddy, Vudem Dashavantha; Giri, Charu Chandra

2016-07-01

Daidzin (7-O-glucoside of daidzein) has several pharmacological benefits in herbal remedy, as antioxidant and shown antidipsotropic activity. Hairy root culture of Psoralea corylifolia L. was developed for biomass and enhanced daidzin production using signalling compounds such as jasmonic acid (JA) and acetyl salicylic acid (ASA). Best response of 2.8-fold daidzin (5.09% DW) with 1 μM JA treatment after second week and 7.3-fold (3.43% DW) with 10 μM JA elicitation after 10th week was obtained from hairy roots compared to untreated control. ASA at 10 μM promoted 1.7-fold increase in daidzin (1.49% DW) content after seventh week compared to control (0.83% DW). Addition of 25 μM ASA resulted in 1.44% DW daidzin (1.5-fold increase) with 0.91% DW in control after fifth week and 1.44% DW daidzin (2.3-fold increase) after eighth week when compared to untreated control (0.62% DW). Reduced biomass with increased daidzin content was facilitated by elicited hairy root cultures.

DISCOVERY OF A CLOSE PAIR OF FAINT DWARF GALAXIES IN THE HALO OF CENTAURUS A

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crnojević, D.; Sand, D. J.; Caldwell, N.

2014-11-10

As part of the Panoramic Imaging Survey of Centaurus and Sculptor (PISCeS), we report the discovery of a pair of faint dwarf galaxies (CenA-MM-Dw1 and CenA-MM-Dw2) at a projected distance of ∼90 kpc from the nearby elliptical galaxy NGC 5128 (CenA). We measure a tip of the red giant branch distance to each dwarf, finding D = 3.63 ± 0.41 Mpc for CenA-MM-Dw1 and D = 3.60 ± 0.41 Mpc for CenA-MM-Dw2, both of which are consistent with the distance to NGC 5128. A qualitative analysis of the color-magnitude diagrams indicates stellar populations consisting of an old, metal-poor red giant branch (≳12 Gyr, [Fe/H] ∼ –1.7 to –1.9). In addition, CenA-MM-Dw1more » seems to host an intermediate-age population as indicated by its candidate asymptotic giant branch stars. The derived luminosities (M{sub V} = –10.9 ± 0.3 for CenA-MM-Dw1 and –8.4 ± 0.6 for CenA-MM-Dw2) and half-light radii (r{sub h} = 1.4 ± 0.04 kpc for CenA-MM-Dw1 and 0.36 ± 0.08 kpc for CenA-MM-Dw2) are consistent with those of Local Group dwarfs. CenA-MM-Dw1's low central surface brightness (μ {sub V,} {sub 0} = 27.3 ± 0.1 mag arcsec{sup –2}) places it among the faintest and most extended M31 satellites. Most intriguingly, CenA-MM-Dw1 and CenA-MM-Dw2 have a projected separation of only 3 arcmin (∼3 kpc): we are possibly observing the first, faint satellite of a satellite in an external group of galaxies.« less

Evaluation of Bioactive Compounds, Pharmaceutical Quality, and Anticancer Activity of Curry Leaf (Murraya koenigii L.)

PubMed Central

Ghasemzadeh, Ali; Jaafar, Hawa Z. E.; Rahmat, Asmah; Devarajan, Thiyagu

2014-01-01

In this study, we investigated some bioactive compounds and pharmaceutical qualities of curry leaf (Murraya koenigii L.) extracts from three different locations in Malaysia. The highest TF and total phenolic (TP) contents were observed in the extracts from Kelantan (3.771 and 14.371 mg/g DW), followed by Selangor (3.146 and 12.272 mg/g DW) and Johor (2.801 and 12.02 mg/g DW), respectively. High quercetin (0.350 mg/g DW), catechin (0.325 mg/g DW), epicatechin (0.678 mg/g DW), naringin (0.203 mg/g DW), and myricetin (0.703 mg/g DW) levels were observed in the extracts from Kelantan, while the highest rutin content (0.082 mg/g DW) was detected in the leaves from Selangor. The curry leaf extract from Kelantan exhibited higher concentration of gallic acid (0.933 mg/g DW) than that from Selangor (0.904 mg/g DW) and Johor (0.813 mg/g DW). Among the studied samples, the ones from Kelantan exhibited the highest radical scavenging activity (DPPH, 66.41%) and ferric reduction activity potential (FRAP, 644.25 μm of Fe(II)/g) followed by those from Selangor (60.237% and 598.37 μm of Fe(II)/g) and Johor (50.76% and 563.42 μm of Fe(II)/g), respectively. A preliminary screening showed that the curry leaf extracts from all the locations exhibited significant anticarcinogenic effects inhibiting the growth of breast cancer cell line (MDA-MB-231) and maximum inhibition of MDA-MB-231 cell was observed with the curry leaf extract from Kelantan. Based on these results, it is concluded that Malaysian curry leaf collected from the North (Kelantan) might be potential source of potent natural antioxidant and beneficial chemopreventive agents. PMID:24693327

Weighted linear least squares estimation of diffusion MRI parameters: strengths, limitations, and pitfalls.

PubMed

Veraart, Jelle; Sijbers, Jan; Sunaert, Stefan; Leemans, Alexander; Jeurissen, Ben

2013-11-01

Linear least squares estimators are widely used in diffusion MRI for the estimation of diffusion parameters. Although adding proper weights is necessary to increase the precision of these linear estimators, there is no consensus on how to practically define them. In this study, the impact of the commonly used weighting strategies on the accuracy and precision of linear diffusion parameter estimators is evaluated and compared with the nonlinear least squares estimation approach. Simulation and real data experiments were done to study the performance of the weighted linear least squares estimators with weights defined by (a) the squares of the respective noisy diffusion-weighted signals; and (b) the squares of the predicted signals, which are reconstructed from a previous estimate of the diffusion model parameters. The negative effect of weighting strategy (a) on the accuracy of the estimator was surprisingly high. Multi-step weighting strategies yield better performance and, in some cases, even outperformed the nonlinear least squares estimator. If proper weighting strategies are applied, the weighted linear least squares approach shows high performance characteristics in terms of accuracy/precision and may even be preferred over nonlinear estimation methods. Copyright © 2013 Elsevier Inc. All rights reserved.

Fatty acid profile and elemental content of avocado (Persea americana Mill.) oil--effect of extraction methods.

PubMed

Reddy, Mageshni; Moodley, Roshila; Jonnalagadda, Sreekanth B

2012-01-01

Interest in vegetable oil extracted from idioblast cells of avocado fruit is growing. In this study, five extraction methods to produce avocado oil have been compared: traditional solvent extraction using a Soxhlet or ultrasound, Soxhlet extraction combined with microwave or ultra-turrax treatment and supercritical fluid extraction (SFE). Traditional Soxhlet extraction produced the most reproducible results, 64.76 ± 0.24 g oil/100 g dry weight (DW) and 63.67 ± 0.20 g oil/100 g DW for Hass and Fuerte varieties, respectively. Microwave extraction gave the highest yield of oil (69.94%) from the Hass variety. Oils from microwave extraction had the highest fatty acid content; oils from SFE had wider range of fatty acids. Oils from Fuerte variety had a higher monounsaturated: saturated FA ratio (3.45-3.70). SFE and microwave extraction produced the best quality oil, better than traditional Soxhlet extraction, with the least amount of oxidizing metals present. Copyright © Taylor & Francis Group, LLC

Ractopamine up take by alfalfa (Medicago sativa) and wheat (Triticum aestivum) from soil.

PubMed

Shelver, Weilin L; DeSutter, Thomas M

2015-08-01

Ractopamine is a beta adrenergic agonist used as a growth promoter in swine, cattle and turkeys. To test whether ractopamine has the potential to accumulate in plants grown in contaminated soil, a greenhouse study was conducted with alfalfa (Medicago sativa) and wheat (Triticum aestivum) grown in two soils having different concentrations of organic matter (1.3% and 2.1%), amended with 0, 0.5, and 10 μg/g of ractopamine. Plant growth ranged from 2.7 to 8.8 g dry weight (dw) for alfalfa, and 8.7 to 40 g dw for wheat and was generally greater in the higher organic matter content soil. The uptake of ractopamine in plant tissues ranged from non-detectable to 897 ng/g and was strongly dependent on soil ractopamine concentration across soil and plant tissue. When adjusted to the total fortified quantities, the amount of ractopamine taken up by the plant tissue was low, <0.01% for either soil. Copyright © 2015. Published by Elsevier B.V.

Synthesis and characterization of seaweed cellulose derived carboxymethyl cellulose.

PubMed

Lakshmi, Duraikkannu Shanthana; Trivedi, Nitin; Reddy, C R K

2017-02-10

In the present study, cellulose (SWC) extracted from green seaweed Ulva fasciata was processed to synthesize carboxymethyl cellulose (SWCMC). The seaweed cellulose (∼15% DW) was first processed for α cellulose extraction (10.1% on DW) followed by the synthesis and characterization of SWCMC. Thin films were prepared using commercial CMC (CCMC), SWCMC and SWCMC-metal nanoparticle (2% wt/v) by solvent evaporation technique. Films were studied for molecular weight, degree of carboxylation, viscosity and characterized by FT-IR and TGA. AFM surface morphology of SWCMC-metal nanoparticle film confirms the uniform distribution of sphere shaped metal nanoparticle on the film surface with the size in the range of 50-75nm. Further, SWCMC film showed antimicrobial activity when prepared with Ag and leaf extract of Azadirachta indica. The biodegradable nature of SWCMC film was confirmed by growing marine fungus Cladosporium spherospermum on CMC agar plates. Thus, SWCMC films exhibit potential applications in cosmetic, food, textiles, medical, agricultural and pharmaceutical industries. Copyright © 2016 Elsevier Ltd. All rights reserved.

Variability in Foliar Ellagitannins of Hippophaë rhamnoides L. and Identification of a New Ellagitannin, Hippophaenin C.

PubMed

Suvanto, Jussi; Tähtinen, Petri; Valkamaa, Saku; Engström, Marica T; Karonen, Maarit; Salminen, Juha-Pekka

2018-01-24

Berries of common sea-buckthorn (Hippophaë rhamnoides L.) are well-known and used for their bioactive components, and while there is a considerable amount of research on the leaves as well, their ellagitannins (ETs) have not been a prominent focus of research. We identified and quantified ten major hydrophilic polyphenols, all ETs, in H. rhamnoides leaves and compared their abundance between 58 plant individuals. Of these compounds, hippophaenin C was characterized as a new ellagitannin by various spectrometric methods. The total concentrations of ETs ranged from 42.5 mg g -1 dry weight (DW) to 109.1 mg g -1 DW between individual plants. Among the ETs, hippophaenin C, stachyurin, and casuarinin were on average the most abundant compounds. Sexes did not differ significantly, while cultivars showed variation in some ETs. These results suggest that H. rhamnoides leaves could be a potential and rich source of several ETs.

Altitude profiles of total chlorinated paraffins in humus and spruce needles from the Alps (MONARPOP).

PubMed

Iozza, Saverio; Schmid, Peter; Oehme, Michael; Bassan, Rodolfo; Belis, Claudio; Jakobi, Gert; Kirchner, Manfred; Schramm, Karl-Werner; Kräuchi, Norbert; Moche, Wolfgang; Offenthaler, Ivo; Weiss, Peter; Simoncic, Primoz; Knoth, Wilhelm

2009-12-01

Chlorinated paraffins (CPs) are toxic, bioaccumulative, persistent, and ubiquitously present in the environment. CPs were analyzed in humus and needle samples, which were taken within the Monitoring Network in the Alpine Region for Persistent and other Organic Pollutants (MONARPOP) at sampling sites of 7 different altitude profiles in the Alps. Gas chromatography combined with electron ionization tandem mass spectrometry (EI-MS/MS) was used for the determination of total CPs (sum of short, medium and long chain CPs). CPs were found in all samples; the concentrations varied between 7 and 199 ng g(-1) dry weight (dw) and within 26 and 460 ng g(-1) dw in humus and needle samples, respectively. A clear vertical tendency within the individual altitude profiles could not be ascertained. Within all altitude profiles, elevated concentrations were observed in humus samples taken between 700 and 900 m and between 1300 and 1500 m. In the needle samples no similar correlation could be observed due to higher variation of the data.

Polychlorinated naphthalenes (PCNs) in riverine and marine sediments of the Laizhou Bay area, North China.

PubMed

Pan, Xiaohui; Tang, Jianhui; Chen, Yingjun; Li, Jun; Zhang, Gan

2011-12-01

PCN congeners were analyzed in marine and riverine sediments of the Laizhou Bay area, North China. Concentrations of PCNs ranged from 0.12 to 5.1 ng g(-)(1) dry weight (dw) with a mean value of 1.1 ng g(-)(1) dw. The levels of PCNs varied largely, with industrial group approximately ten folds higher than those of the rural in riverine sediment. A strong impact by direct discharge from local factories was suggested. Similar compositional profiles were found within groups. High resemblance of compositional profiles between industrial samples and Halowax 1014 was observed. It was indicated that PCNs in riverine sediments were mainly from release of industrial usage, with additional contributions from industrial thermal process at certain sites. In marine sediments, it was suggested that PCNs along the coast of Laizhou Bay were mainly controlled by riverine input. While in the central bay, PCN distributions were possibly impacted by combined multiple factors. Copyright © 2011 Elsevier Ltd. All rights reserved.

Analysis of by-product formation and sugar monomerization in sugarcane bagasse pretreated at pilot plant scale: differences between autohydrolysis, alkaline and acid pretreatment.

PubMed

van der Pol, Edwin; Bakker, Rob; van Zeeland, Alniek; Sanchez Garcia, David; Punt, Arjen; Eggink, Gerrit

2015-04-01

Sugarcane bagasse is an interesting feedstock for the biobased economy since a large fraction is polymerized sugars. Autohydrolysis, alkaline and acid pretreatment conditions combined with enzyme hydrolysis were used on lignocellulose rich bagasse to acquire monomeric. By-products found after pretreatment included acetic, glycolic and coumaric acid in concentrations up to 40, 21 and 2.5 g/kg dry weight bagasse respectively. Alkaline pretreated material contained up to 45 g/kg bagasse DW of sodium. Acid and autohydrolysis pretreatment results in a furan formation of 14 g/kg and 25 g/kg DW bagasse respectively. Enzyme monomerization efficiencies of pretreated solid material after 72 h were 81% for acid pretreatment, 77% for autohydrolysis and 57% for alkaline pretreatment. Solid material was washed with superheated water to decrease the amount of by-products. Washing decreased organic acid, phenol and furan concentrations in solid material by at least 60%, without a major sugar loss. Copyright © 2015 Elsevier Ltd. All rights reserved.

Polycyclic aromatic hydrocarbons in the largest deepwater port of East China Sea: impact of port construction and operation.

PubMed

Li, Juan-Ying; Cui, Yu; Su, Lei; Chen, Yiqin; Jin, Ling

2015-08-01

PAHs were analyzed for samples of seawater, sediment, and oyster (Saccostrea cucullata) collected from Yangshan Port, East China between 2012 and 2013. Concentrations of ∑PAHs in seawater (180-7,700 ng/L) and oyster (1,100-29,000 ng/g dry weight (dw)) fell at the higher end of the global concentration range, while sediment concentrations (120-780 ng/g dw) were generally comparable to or lower than those reported elsewhere. PAHs in the particulate phase accounted for 85% (52-93%) of the total PAHs in seawater. Congener profile analysis revealed that PAHs in waters originate mainly from petrogenic sources, while high-temperature combustion processes are the predominant sources for sediment. ∑PAHs in oyster well correlated with ∑PAHs in the particulate phase, suggesting particle ingestion as an important pathway for bioaccumulation of PAHs. Cancer risk assessment of PAHs in oyster indicated high human health risks posed by these chemicals to the coastal population consuming this seafood.

Analysis of Trace Quaternary Ammonium Compounds (QACs) in Vegetables Using Ultrasonic-Assisted Extraction and Gas Chromatography-Mass Spectrometry.

PubMed

Xiang, Lei; Wang, Xiong-Ke; Li, Yan-Wen; Huang, Xian-Pei; Wu, Xiao-Lian; Zhao, Hai-Ming; Li, Hui; Cai, Quan-Ying; Mo, Ce-Hui

2015-08-05

A reliable, sensitive, and cost-effective method was developed for determining three quaternary ammonium compounds (QACs) including dodecyltrimethylammonium chloride, cetyltrimethylammonium chloride, and didodecyldimethylammonium chloride in various vegetables using ultrasonic-assisted extraction and gas chromatography-mass spectrometry. The variety and acidity of extraction solvents, extraction times, and cleanup efficiency of sorbents were estimated to obtain an optimized procedure for extraction of the QACs in nine vegetable matrices. Excellent linearities (R(2) > 0.992) were obtained for the analytes in the nine matrices. The limits of detection and quantitation were 0.7-6.0 and 2.3-20.0 μg/kg (dry weight, dw) in various matrices, respectively. The recoveries in the nine matrices ranged from 70.5% to 108.0% with relative standard deviations below 18.0%. The developed method was applied to determine the QACs in 27 vegetable samples collected from Guangzhou in southern China, showing very high detection frequency with a concentration of 23-180 μg/kg (dw).

Investigation of cellular detonation structure formation via linear stability theory and 2D and 3D numerical simulations

NASA Astrophysics Data System (ADS)

Borisov, S. P.; Kudryavtsev, A. N.

2017-10-01

Linear and nonlinear stages of the instability of a plane detonation wave (DW) and the subsequent process of formation of cellular detonation structure are investigated. A simple model with one-step irreversible chemical reaction is used. The linear analysis is employed to predict the DW front structure at the early stages of its formation. An emerging eigenvalue problem is solved with a global method using a Chebyshev pseudospectral method and the LAPACK software library. A local iterative shooting procedure is used for eigenvalue refinement. Numerical simulations of a propagation of a DW in plane and rectangular channels are performed with a shock capturing WENO scheme of 5th order. A special method of a computational domain shift is implemented in order to maintain the DW in the domain. It is shown that the linear analysis gives certain predictions about the DW structure that are in agreement with the numerical simulations of early stages of DW propagation. However, at later stages, a merger of detonation cells occurs so that their number is approximately halved. Computations of DW propagation in a square channel reveal two different types of spatial structure of the DW front, "rectangular" and "diagonal" types. A spontaneous transition from the rectangular to diagonal type of structure is observed during propagation of the DW.

Effects of adding bulking agent, inorganic nutrient and microbial inocula on biopile treatment for oil-field drilling waste.

PubMed

Ma, Jie; Yang, Yongqi; Dai, Xiaoli; Chen, Yetong; Deng, Hanmei; Zhou, Huijun; Guo, Shaohui; Yan, Guangxu

2016-05-01

Contamination from oil-field drilling waste is a worldwide environmental problem. This study investigated the performance of four bench-scale biopiles in treating drilling waste: 1) direct biopile (DW), 2) biopile plus oil-degrading microbial consortium (DW + M), 3) biopile plus microbial consortium and bulking agents (saw dust) (DW + M + BA), 4) biopile plus microbial consortium, bulking agents, and inorganic nutrients (Urea and K2HPO4) (DW + M + BA + N). Ninety days of biopiling removed 41.0%, 44.0%, 55.7% and 87.4% of total petroleum hydrocarbon (TPH) in the pile "DW", "DW + M", "DW + M + BA", and "DW + M + BA + N" respectively. Addition of inorganic nutrient and bulking agents resulted in a 56.9% and 26.6% increase in TPH removal efficiency respectively. In contrast, inoculation of hydrocarbon-degrading microorganisms only slightly enhanced the contaminant removal (increased 7.3%). The biopile with stronger contaminant removal also had higher pile temperature and lower pile pH (e.g., in "DW + M + BA + N"). GC-MS analysis shows that biopiling significantly reduced the total number of detected contaminants and changed the chemical composition. Overall, this study shows that biopiling is an effective remediation technology for drilling waste. Adding inorganic nutrients and bulking agents can significantly improve biopile performance while addition of microbial inocula had minimal positive impacts on contaminant removal. Copyright © 2016 Elsevier Ltd. All rights reserved.

Simulation of Oscillatory Domain Wall Motion Driven by Spin Waves in Nanostrip with Perpendicular Magnetic Anisotropy

NASA Astrophysics Data System (ADS)

Lee, Shang Fan; Chang, Liang Juan; Spintronics Laboratory Team

2014-03-01

We numerically investigate the spin waves (SW) induced domain wall (DW) oscillatory motion in a nanostrip with perpendicular magnetic anisotropy by means of micromagnetic simulation. SW carries spin angular momentum and can interact with DWs via Spin Transfer Torque (STT). Propagating SW can drive a DW motion depending on the in-plane tilt angle φ of the wall magnetization. We calculate the instantaneous velocity of DWs as a function of φwith different SW frequency f. We find that the DW motion under propagating SW depends not only on the frequencies f, but also on the in-plane tilt angle φ. The nanostrip considered is 50 nm wide and 4000 nm long. A DW at the center is subjected to a SW source 500 nm apart on the left with amplitude in the transverse direction and varying frequency f. The motions of the DW induced by the SW are accompanied by in-plane rotation of magnetization of DW. Once rotated by 90 degrees, the DW shows a backward motion towards the SW source. The oscillatory amplitude and frequency of the DW motion is analyzed. A phase diagram will be presented. This study provides new perspectives for the control and manipulation of DW in a nanostrip. Financial supports by Academia Sinica and National Science Council are acknowledged

77 FR 61562 - Atlantic Highly Migratory Species; 2013 Atlantic Shark Commercial Fishing Season

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-10

... 9.1 (20,015 lb 50.0 (110,230 50.0 (110,230 Shark Research Quota. quotas. dw). dw). lb dw). lb dw... Amendment 2 and Amendment 3 to the 2006 Consolidated HMS FMP and the Environmental Assessment (EA) that... the EA with the 2011 shark quota specifications rule. Thus, NMFS has limited flexibility to modify the...

Oligonucleotide-genotyping as a method of detecting the HLA-DR2 (DRw15)-Dw2, -DR2 (DRw15)-Dw12, -DR4-Dw15, and -DR4-D"KT2" haplotypes in the Japanese population.

PubMed

Obata, F; Ito, I; Kaneko, T; Ohkubo, M; Ishimoto, A L; Abe, A; Kashiwagi, N

1989-05-01

We synthesized pairs of four different oligonucleotides, F22, F29, F42, and F158, to analyse the HLA-DR2 (DRw15) and -DR4 haplotypes in the Japanese population. After enzymatically amplifying the HLA-DRB1 gene, we hybridized the oligonucleotide probes with DNA extracted from 42 donors. Hybridization was completed between F22 and the DNA of haplotype DR2 (DRw15)-Dw2, between F29 and the DNA of DR2 (DRw15)-Dw12, between F42 and the DNA of DR4-D"KT2", and between F158 and the DNA of DR4-Dw15. In keeping with the nucleotide sequences of the probes, F29 hybridized also with DNA from the DR9-Dw23 haplotype and F158 with that from some of the DRw8 haplotypes (DRw8-Dw8.3) in the Japanese population. Results of this study demonstrate that the four oligonucleotides make useful probes for detecting the haplotypes above.

High Efficiency, Low Distortion 3D Diffusion Tensor Imaging with Variable Density Spiral Fast Spin Echoes (3D DW VDS RARE)

PubMed Central

Frank, Lawrence R.; Jung, Youngkyoo; Inati, Souheil; Tyszka, J. Michael; Wong, Eric C.

2009-01-01

We present an acquisition and reconstruction method designed to acquire high resolution 3D fast spin echo diffusion tensor images while mitigating the major sources of artifacts in DTI - field distortions, eddy currents and motion. The resulting images, being 3D, are of high SNR, and being fast spin echoes, exhibit greatly reduced field distortions. This sequence utilizes variable density spiral acquisition gradients, which allow for the implementation of a self-navigation scheme by which both eddy current and motion artifacts are removed. The result is that high resolution 3D DTI images are produced without the need for eddy current compensating gradients or B0 field correction. In addition, a novel method for fast and accurate reconstruction of the non-Cartesian data is employed. Results are demonstrated in the brains of normal human volunteers. PMID:19778618

Diffusion and ideal MRI techniques to characterize limb-girdle muscular dystrophy

NASA Astrophysics Data System (ADS)

Hernández-Salazar, G.; Hidalgo-Tobon, S.; Vargas-Cañas, S.; Marrufo-Melendez, O.; Solis-Najera, S.; Taboada-Barajas, J.; Rodríguez, A. O.; Delgado-Hernández, R.

2012-10-01

Limb-girdle muscular dystrophies (LGMD) are a group of autosomal dominantly or recessively inherited muscular dystrophies that also present with primary proximal (limb-girdle) muscle weakness. In the thigh, muscles at the back are affected, with a tendency to preserve the tibialis anterior and gastrocnemius. The aim of this study was to compare quantitative MRI measurements from IDEAL-based imaging and DW imaging in the thigh muscles of adults with LGMDs and healthy volunteers(HC). Six women (three patients and three healthy volunteers) were examined. Imaging experiments were conducted on a 1.5T GE scanner (General Electric Medical Systems. Milwaukee). T1 IDEAL 2D images and diffusion images were acquired. Results demonstrated that the use of noninvasive MRI techniques may provide the means to characterize the muscle through quantitative methods to determine the percentage of fat and ADC values.

Multiparametric magnetic resonance imaging for the assessment of extracapsular invasion and other staging parameters in patients with prostate cancer candidates for radical prostatectomy.

PubMed

Lista, F; Gimbernat, H; Cáceres, F; Rodríguez-Barbero, J M; Castillo, E; Angulo, J C

2014-06-01

the proper evaluation of the extracapsular extension (ECE), the invasion of seminal vesicles and regional lymph nodes are necessary to plan the treatment of localized prostate cancer. A model that assesses the risk of ECE in the specimen considering the clinical, histological and imaging findings is defined. prospective study in 85 patients with prostate cancer treated with radical prostatectomy. Prostate biopsy was performed 4 weeks before multiparametric study (mpMRI). mpMRI included T2-weighted endorectal magnetic resonance imaging (T2W-MRI), diffusion-weighted magnetic resonance imaging (DW-MRI) and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). The apparent diffusion coefficient (ADC) was also measured. A study of consistency (k) was assessed comparing receiver operating characteristic (ROC) curve and area under the curve (AUC), which were obtained in each case (Z). Finally, a regression model was performed to predict ECE. the mean age was 63.7 ± 6.9 years and the mean value of PSA 12.6 ± 13.8. In 31.7% of cases, digital rectal examination was suspicious for malignancy. Prostatectomy specimen showed pT2a in 12 cases (14%), pT2b in 3 (3%), pT2c in 37 (43%), pT3a in 19(22%) and pT3b 14 cases (17%). ECE was evidenced in 33 (39%) of the specimens, seminal vesicle invasion in 14 (16.5%) and pelvic node involvement in 5 patients (6%). The consistency in the evaluation of ECE (image and pathological studies) was .35 for MRI (sensitivity .33, specificity .96) and .62 for mpMRI (sensitivity .58, specificity .98). Mean value of ADC was .76 ± .2 in patients with ECE. This value was not associated with Gleason score (P = .2) or with PSA value (P = .6). AUC value as predictor of ECE was of 65% for MRI, 78% for mpMRI and 50% ADC (Z = .008). Univariate analysis demonstrated that ECE probability increases with each Gleason score point, whilst this probability increases 1.06 times with each PSA point, and decreases .3 times with each point of ADC. Multivariate analysis confirmed that ADC value is a slight protective factor against ECE (OR = .01; CI 95% .002-.14). The consistency in the evaluation of seminal vesicles was .43 for MRI and .67 for mpMRI. AUC was 69% and 82% respectively (Z = .02). The consistency in the evaluation of positive lymph nodes was .4 for MRI and .7 for mpMRI. AUC was 68% and 88% respectively (Z = .36). multiparametric study allows to carry out a more proper preoperative evaluation of ECE than convectional MRI. The most reliable predictors of ECE are DW-MRI combined with DCE-MRI, ADC coefficient and Gleason score. The superiority of mpMRI is also demonstrated for detection of seminal vesicles invasion, but not for the evaluation of lymph nodes invasion. Copyright © 2013 AEU. Published by Elsevier Espana. All rights reserved.

Diffusion pseudonormalization and clinical outcome in term neonates with hypoxic-ischemic encephalopathy.

PubMed

Hayakawa, Katsumi; Koshino, Sachiko; Tanda, Koichi; Nishimura, Akira; Sato, Osamu; Morishita, Hiroyuki; Ito, Takaaki

2018-06-01

Pseudonormalization of diffusion-weighted magnetic resonance imaging (MRI) can lead to underestimation of brain injury in newborns with hypoxic-ischemic encephalopathy (HIE), posing a significant problem. We have noticed that some neonates show pseudonormalization negativity on diffusion-weighted imaging. To compare pseudonormalization negativity with clinical outcomes. Seventeen term neonates with moderate or severe HIE underwent therapeutic hypothermia. They were examined by MRI twice at mean ages of 3 days and 10 days. We evaluated the presence of restricted diffusion, and also the presence or absence of pseudonormalization, by diffusion-weighted imaging at the time of the second MRI, and correlated the results with clinical outcome. DWI demonstrated no abnormality in seven neonates. Among the 10 neonates with abnormal diffusion-weighted imaging findings, 2 were positive for pseudonormalization and 8 were negative. Among neonates with normal diffusion-weighted imaging findings and with positivity for pseudonormalization, none had major disability. Among the eight neonates with pseudonormalization negativity, all but one, who was lost to follow-up, had major disability. Abnormal diffusion-weighted imaging with pseudonormalization negativity might be predictive of severe brain injury and major disability. The second-week MRI is important for the judgment of pseudonormalization.

Diffusion weighted magnetic resonance imaging and its recent trend—a survey

PubMed Central

Chilla, Geetha Soujanya; Tan, Cher Heng

2015-01-01

Since its inception in 1985, diffusion weighted magnetic resonance imaging has been evolving and is becoming instrumental in diagnosis and investigation of tissue functions in various organs including brain, cartilage, and liver. Even though brain related pathology and/or investigation remains as the main application, diffusion weighted magnetic resonance imaging (DWI) is becoming a standard in oncology and in several other applications. This review article provides a brief introduction of diffusion weighted magnetic resonance imaging, challenges involved and recent advancements. PMID:26029644

Role of PROPELLER-DWI of the prostate in reducing distortion and artefact from total hip replacement metalwork.

PubMed

Czarniecki, Marcin; Caglic, Iztok; Grist, James T; Gill, Andrew B; Lorenc, Kamil; Slough, Rhys A; Priest, Andrew N; Barrett, Tristan

2018-05-01

To compare image quality, artefact, and distortion in standard echo-planar imaging (EPI) with periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) for prostate magnetic resonance imaging (MRI) diffusion-weighted imaging (DWI) in patients with previous total hip replacement (THR). 21 male subjects with a clinical suspicion for, or known prostate cancer and previous THR were scanned at 1.5 T using a phased-array body coil. DWI was obtained using single-shot EPI and PROPELLER techniques using fat saturation (PROPELLER-DWI-FS), and without (PROPELLER-DWI-NFS). Image quality (the overall impression of diagnostic quality) was compared to T 2 -weighted (T2WI) imaging using a 5-point Likert scale, with diffusion sequences additionally scored for artefact and distortion according to a 4-point scale, with artefact defined as the amount of prostate affected and distortion as the degree of warping of the organ. The T2W and DW image volumes were compared to produce quantitative distortion maps. A two-sample Wilcoxon test compared the qualitative scores, with inter-reader variability calculated using Cohen's kappa. 21 patients were included in the study, with an average age of 70.4 years and PSA 9.2 ng/ml. Hip metalwork was present bilaterally in 3 patients, left-sided in 9, and right-sided in 9. PROPELLER-DWI-FS significantly improved image quality (p < 0.01) and reduced distortion (p < 0.01) when compared to standard EP-DWI. Artefact was not shown to be significantly improved. The last 5 patients in the study were additionally imaged with PROPELLER-DWI-NFS, which resulted in a significant reduction in artefact compared to EP-DWI (p < 0.05). Quantitative distortion was significantly lower compared to EP-DWI for both PROPELLER with fat saturation (p < 0.01) and without fat saturation (p < 0.01). PROPELLER-DWI demonstrates better image quality and decreases both artefact and distortion compared to conventional echo planar sequences in patients with hip metalwork. Copyright © 2018 Elsevier B.V. All rights reserved.

Emulsion-Based Intradermal Delivery of Melittin in Rats.

PubMed

Han, Sang Mi; Kim, Se Gun; Pak, Sok Cheon

2017-05-19

Bee venom (BV) has long been used as a traditional medicine. The aim of the present study was to formulate a BV emulsion with good rheological properties for dermal application and investigate the effect of formulation on the permeation of melittin through dermatomed rat skin. A formulated emulsion containing 1% ( w / v ) BV was prepared. The emulsion was compared with distilled water (DW) and 25% ( w / v ) N -methyl-2-pyrrolidone (NMP) in DW. Permeation of melittin from aqueous solution through the dermatomed murine skin was evaluated using the Franz diffusion cells. Samples of receptor cells withdrawn at pre-determined time intervals were measured for melittin amount. After the permeation study, the same skin was used for melittin extraction. In addition, a known amount of melittin (5 μg/mL) was added to stratum corneum, epidermis, and dermis of the rat skin, and the amount of melittin was measured at pre-determined time points. The measurement of melittin from all samples was done with HPLC-MS/MS. No melittin was detected in the receptor phase at all time points in emulsion, DW, or NMP groups. When the amount of melittin was further analyzed in stratum corneum, epidermis, and dermis from the permeation study, melittin was still not detected. In an additional experiment, the amount of melittin added to all skin matrices was corrected against the amount of melittin recovered. While the total amount of melittin was retained in the stratum corneum, less than 10% of melittin remained in epidermis and dermis within 15 and 30 min, respectively. Skin microporation with BV emulsion facilitates the penetration of melittin across the stratum corneum into epidermis and dermis, where emulsified melittin could have been metabolized by locally-occurring enzymes.

Poly- and perfluoroalkylated substances (PFASs) in water, sediment and fish muscle tissue from Lake Tana, Ethiopia and implications for human exposure.

PubMed

Ahrens, Lutz; Gashaw, Habiba; Sjöholm, Margareta; Gebrehiwot, Solomon Gebreyohannis; Getahun, Abebe; Derbe, Ermias; Bishop, Kevin; Åkerblom, Staffan

2016-12-01

Lake Tana is Ethiopia's largest lake and there are plans to increase the harvest of fish from the lake. The objective of this study was to assess the levels of poly- and perfluoroalkyl substances (PFASs) in different compartments of the lake (water, sediment, and fish muscle tissue), and its implications for human exposure. The results showed higher PFAS concentrations in piscivorous fish species (Labeobarbus megastoma and Labeobarbus gorguari) than non-piscivorous species (Labeobarbus intermedius, Oreochromis niloticus and Clarias gariepinus) and also spatial distribution similarities. The ∑PFAS concentrations ranged from 0.073 to 5.6 ng L -1 (on average, 2.9 ng L -1 ) in surface water, 0.22-0.55 ng g -1 dry weight (dw) (on average, 0.30 ng g -1 dw) in surface sediment, and non-detected to 5.8 ng g -1 wet weight (ww) (on average, 1.2 ng g -1 ww) in all fish species. The relative risk (RR) indicates that the consumption of fish contaminated with perfluorooctane sulfonate (PFOS) will likely not cause any harmful effects for the Ethiopian fish eating population. However, mixture toxicity of the sum of PFASs, individual fish consumption patterns and increasing fish consumption are important factors to consider in future risk assessments. Copyright © 2016 Elsevier Ltd. All rights reserved.

Assessment of the occupational and environmental risks of hexabromocyclododecane (HBCD) in China.

PubMed

Yi, Shan; Liu, Jian-Guo; Jin, Jun; Zhu, Jing

2016-05-01

In 2013, hexabromocyclododecane (HBCD) was listed in the Stockholm Convention on Persistent Organic Pollutants obligated to be phased out worldwide. China is a major producer and user of HBCD. Based on Chinese HBCD production and processing conditions, we classified the existing 599 HBCD production and processing plants into six occupational exposure scenarios. We also used occupational environmental monitoring and occupational health risk assessment models to estimate exposure levels. Occupational internal exposure levels for HBCD in China were estimated to range from 0.61 to 840 μg kg(-1) d(-1), which suggests that approximately 453-840 workers, or 72% of all workers in this industry, may have occupational exposure risk. As such, the occupational risks of HBCD should not be ignored. In our study area, HPLC-MS/MS revealed HBCD concentrations ranging from 0.11 to 560 ng g dry weight (dw)(-1), 20.4-24.2 ng g dw(-1), and 166-1964 ng g lipid weight (lw)(-1) in soil, sediment, and biological samples, respectively, consistent with previous monitoring results. These data suggest potential risk to marine environments due to sustained and large-scale HBCD production and processing. Thus, timely measures to control HBCD-related risk are necessary and may bring significant occupational health and environmental benefits in areas where HBCD is prevalent. Copyright © 2016 Elsevier Ltd. All rights reserved.

Metabolite-cycled density-weighted concentric rings k-space trajectory (DW-CRT) enables high-resolution 1 H magnetic resonance spectroscopic imaging at 3-Tesla.

PubMed

Steel, Adam; Chiew, Mark; Jezzard, Peter; Voets, Natalie L; Plaha, Puneet; Thomas, Michael Albert; Stagg, Charlotte J; Emir, Uzay E

2018-05-17

Magnetic resonance spectroscopic imaging (MRSI) is a promising technique in both experimental and clinical settings. However, to date, MRSI has been hampered by prohibitively long acquisition times and artifacts caused by subject motion and hardware-related frequency drift. In the present study, we demonstrate that density weighted concentric ring trajectory (DW-CRT) k-space sampling in combination with semi-LASER excitation and metabolite-cycling enables high-resolution MRSI data to be rapidly acquired at 3 Tesla. Single-slice full-intensity MRSI data (short echo time (TE) semi-LASER TE = 32 ms) were acquired from 6 healthy volunteers with an in-plane resolution of 5 × 5 mm in 13 min 30 sec using this approach. Using LCModel analysis, we found that the acquired spectra allowed for the mapping of total N-acetylaspartate (median Cramer-Rao Lower Bound [CRLB] = 3%), glutamate+glutamine (8%), and glutathione (13%). In addition, we demonstrate potential clinical utility of this technique by optimizing the TE to detect 2-hydroxyglutarate (long TE semi-LASER, TE = 110 ms), to produce relevant high-resolution metabolite maps of grade III IDH-mutant oligodendroglioma in a single patient. This study demonstrates the potential utility of MRSI in the clinical setting at 3 Tesla.

Effect of Fe2+ and Mn2+ addition on growth and β-carotene production of Dunaliella salina

NASA Astrophysics Data System (ADS)

Mayasari, E.; Raya, I.; Natsir, H.

2018-03-01

Dunaliella salina is a unicellular chlorophyte, which could grow in a wide range of harsh environmental condition. Under growth-limitation conditions, D.salina was known as famous for a high β-carotene producer with up to 10% of its dry cell weights, therefore it could be a β-carotene supplement. The research aimed to find out the effect of Iron (Fe2+) and Manganese (Mn2+) towards β-carotene productivity as result of oxidative stress from the second photosystem (PS II). The analysis method was carried out by the ultrasonic extraction for short and cheap lyses of phytoplankton biomasses; infra-red (IR) to find out the interaction metal ion, and UV/VIS spectrophotometer to determine the β-carotene concentration from phytoplankton the crude extract. The result showed that the interaction occurred between metal ions and M-N, -O-M and M←OH-C groups in the amino acid of phytoplankton. The highest impact was indicated on 0.3 ppm Fe2+ to D. Salina. The highest β-carotene concentration was 13.08 μg/g DW for 0.3 ppm Fe2+ and 8.08 μg/g DW for 0.8 ppm Mn2+. The dry weight concentrations of β-carotene indicated that D. salina with 0.6 ppm Fe2+ addition had more potential as a β-carotene supplement.

Occurrence of organic UV filters and metabolites in lebranche mullet (Mugil liza) from Brazil.

PubMed

Molins-Delgado, Daniel; Muñoz, Ramón; Nogueira, Sylvia; Alonso, Mariana B; Torres, João Paulo; Malm, Olaf; Ziolli, Roberta Lourenço; Hauser-Davis, Rachel Ann; Eljarrat, Ethel; Barceló, Damià; Díaz-Cruz, M Silvia

2018-03-15

UV filters (UV-Fs) constitute a heterogeneous group of chemicals used as protection against the effects of UV radiation, widely used in all sort of goods and ubiquitous in the environment. The presence of these chemicals in fish is a matter of concern, because many UV-Fs display hormonal activity. In this study, muscle, gills, and liver from 11 Mugil liza individuals from the highly urbanized Guanabara Bay (Rio de Janeiro, Brazil) were analysed in order to detect eight UV-Fs and metabolites (4-dihydroxybenzophenone [BP1] (2-hydroxy-4-methoxybenzophenone [BP3], 4-methylbenzylidiene camphor [4MBC], ethylhexyl methoxycinnamate [EHMC], ethylhexyl dimethyl p-aminobenzoic acid [ODPABA], octocrylene [OC], 4-hydroxybenzophenone [4HB], and 4,4'-dihydroxybenzophenone [4DHB]) using liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Results showed that both target UV-Fs and metabolites were ubiquitous in the analysed tissues. Lower concentrations were observed in muscle and gills (3.07-31.6ngg -1 dry weight (dw)), whereas in liver significant amounts of metabolites (5.47-451ngg -1 dw) were present. With the concentrations determined in the fish, an estimation of the daily intake revealed that consumption of muscle in the diet represent from 0.3 to 15.2ng UV-Fs (kg body weight -1 ) d -1 , higher than those reported in fish for selected persistent organic pollutants (POPs). Copyright © 2017 Elsevier B.V. All rights reserved.

Super-resolution reconstruction of diffusion parameters from diffusion-weighted images with different slice orientations.

PubMed

Van Steenkiste, Gwendolyn; Jeurissen, Ben; Veraart, Jelle; den Dekker, Arnold J; Parizel, Paul M; Poot, Dirk H J; Sijbers, Jan

2016-01-01

Diffusion MRI is hampered by long acquisition times, low spatial resolution, and a low signal-to-noise ratio. Recently, methods have been proposed to improve the trade-off between spatial resolution, signal-to-noise ratio, and acquisition time of diffusion-weighted images via super-resolution reconstruction (SRR) techniques. However, during the reconstruction, these SRR methods neglect the q-space relation between the different diffusion-weighted images. An SRR method that includes a diffusion model and directly reconstructs high resolution diffusion parameters from a set of low resolution diffusion-weighted images was proposed. Our method allows an arbitrary combination of diffusion gradient directions and slice orientations for the low resolution diffusion-weighted images, optimally samples the q- and k-space, and performs motion correction with b-matrix rotation. Experiments with synthetic data and in vivo human brain data show an increase of spatial resolution of the diffusion parameters, while preserving a high signal-to-noise ratio and low scan time. Moreover, the proposed SRR method outperforms the previous methods in terms of the root-mean-square error. The proposed SRR method substantially increases the spatial resolution of MRI that can be obtained in a clinically feasible scan time. © 2015 Wiley Periodicals, Inc.

Quantifying Quality of Life and Disability of Patients with Advanced Schistosomiasis Japonica

PubMed Central

Jia, Tie-Wu; Utzinger, Jürg; Deng, Yao; Yang, Kun; Li, Yi-Yi; Zhu, Jin-Huan; King, Charles H.; Zhou, Xiao-Nong

2011-01-01

Background The Chinese government lists advanced schistosomiasis as a leading healthcare priority due to its serious health and economic impacts, yet it has not been included in the estimates of schistosomiasis burden in the Global Burden of Disease (GBD) study. Therefore, the quality of life and disability weight (DW) for the advanced cases of schistosomiasis japonica have to be taken into account in the re-estimation of burden of disease due to schistosomiasis. Methodology/Principal Findings A patient-based quality-of-life evaluation was performed for advanced schistosomiasis japonica. Suspected or officially registered advanced cases in a Schistosoma japonicum-hyperendemic county of the People's Republic of China (P.R. China) were screened using a short questionnaire and physical examination. Disability and morbidity were assessed in confirmed cases, using the European quality of life questionnaire with an additional cognitive dimension (known as the “EQ-5D plus”), ultrasonography, and laboratory testing. The age-specific DW of advanced schistosomiasis japonica was estimated based on patients' self-rated health scores on the visual analogue scale of the questionnaire. The relationships between health status, morbidity and DW were explored using multivariate regression models. Of 506 candidates, 215 cases were confirmed as advanced schistosomiasis japonica and evaluated. Most of the patients reported impairments in at least one health dimension, such as pain or discomfort (90.7%), usual activities (87.9%), and anxiety or depression (80.9%). The overall DW was 0.447, and age-specific DWs ranged from 0.378 among individuals aged 30–44 years to 0.510 among the elderly aged ≥60 years. DWs are positively associated with loss of work capacity, psychological abnormality, ascites, and active hepatitis B virus, while splenectomy and high albumin were protective factors for quality of life. Conclusions/Significance These patient-preference disability estimates could provide updated data for a revision of the GBD, as well as for evidence-based decision-making in P.R. China's national schistosomiasis control program. PMID:21358814

The extent of arsenic and of metal uptake by aboveground tissues of Pteris vittata and Cyperus involucratus growing in copper- and cobalt-rich tailings of the Zambian copperbelt.

PubMed

Kříbek, Bohdan; Mihaljevič, Martin; Sracek, Ondra; Knésl, Ilja; Ettler, Vojtěch; Nyambe, Imasiku

2011-08-01

The extent of arsenic (As) and metal accumulation in fronds of the As hyperaccumulator Pteris vittata (Chinese brake fern) and in leaves of Cyperus involucratus, which grow on the surface of an old flotation tailings pond in the Zambian Copperbelt province, was studied. The tailings consist of two types of material with distinct chemical composition: (1) reddish-brown tailings rich in As, iron (Fe), and other metals, and (2) grey-green tailings with a lower content of As, Fe, and other metals, apart from manganese (Mn). P. vittata accumulates from 2350 to 5018 μg g(-1) As (total dry weight [dw]) in its fronds regardless of different total and plant-available As concentrations in both types of tailings. Concentrations of As in C. involucratus leaves are much lower (0.24-30.3 μg g(-1) dw). Contents of copper (Cu) and cobalt (Co) in fronds of P. vittata (151-237 and 18-38 μg g(-1) dw, respectively) and in leaves of C. involucratus (96-151 and 9-14 μg g(-1) dw, respectively) are high, whereas concentrations of other metals (Fe, Mn, and zinc [Zn]) are low and comparable with contents of the given metals in common plants. Despite great differences in metal concentrations in the two types of deposited materials, concentrations of most metals in plant tissues are very similar. This indicates an exclusion or avoidance mechanism operating when concentrations of the metals in substrate are particularly high. The results of the investigation show that Chinese brake fern is not only a hyperaccumulator of As but has adapted itself to high concentrations of Cu and Co in flotation tailings of the Zambian Copperbelt.

Antibiotics and Antibiotic Resistance Genes in Sediment of Honghu Lake and East Dongting Lake, China.

PubMed

Yang, Yuyi; Cao, Xinhua; Lin, Hui; Wang, Jun

2016-11-01

Sediment is an ideal medium for the aggregation and dissemination of antibiotics and antibiotic resistance genes (ARGs). The levels of antibiotics and ARGs in Honghu Lake and East Dongting Lake of central China were investigated in this study. The concentrations of eight antibiotics (four sulfonamides and four tetracyclines) in Honghu Lake were in the range 90.00-437.43 μg kg -1 (dry weight (dw)) with mean value of 278.21 μg kg -1 dw, which was significantly higher than those in East Dongting Lake (60.02-321.04 μg kg -1 dw, mean value of 195.70 μg kg -1 dw). Among the tested three sulfonamide resistance genes (sul) and eight tetracycline resistance genes (tet), sul1, sul2, tetA, tetC, and tetM had 100 % detection frequency in sediment samples of East Dongting Lake, while only sul1, sul2, and tetC were observed in all samples of Honghu Lake. The relative abundance of sul2 was higher than that of sul1 at p < 0.05 level in both lakes. The relative abundance of tet genes in East Dongting Lake was in the following order: tetM > tetB > tetC > tetA. The relative abundance of sul1, sul2, and tetC in East Dongting Lake was significantly higher than those in Honghu Lake. The abundance of background bacteria may play an important role in the horizontal spread of sul2 and tetC genes in Honghu Lake and sul1 in East Dongting Lake, respectively. Redundancy analysis indicated that tetracyclines may play a more important role than sulfonamides in the abundance of sul1, sul2, and tetC gens in Honghu Lake and East Dongting Lake.

Quantitative multiphase model for hydrothermal liquefaction of algal biomass

DOE PAGES

Li, Yalin; Leow, Shijie; Fedders, Anna C.; ...

2017-01-17

Here, optimized incorporation of hydrothermal liquefaction (HTL, reaction in water at elevated temperature and pressure) within an integrated biorefinery requires accurate models to predict the quantity and quality of all HTL products. Existing models primarily focus on biocrude product yields with limited consideration for biocrude quality and aqueous, gas, and biochar co-products, and have not been validated with an extensive collection of feedstocks. In this study, HTL experiments (300 °C, 30 min) were conducted using 24 different batches of microalgae feedstocks with distinctive feedstock properties, which resulted in a wide range of biocrude (21.3–54.3 dry weight basis, dw%), aqueous (4.6–31.2more » dw%), gas (7.1–35.6 dw%), and biochar (1.3–35.0 dw%) yields. Based on these results, a multiphase component additivity (MCA) model was introduced to predict yields and characteristics of the HTL biocrude product and aqueous, gas, and biochar co-products, with only feedstock biochemical (lipid, protein, carbohydrate, and ash) and elemental (C/H/N) composition as model inputs. Biochemical components were determined to distribute across biocrude product/HTL co-products as follows: lipids to biocrude; proteins to biocrude > aqueous > gas; carbohydrates to gas ≈ biochar > biocrude; and ash to aqueous > biochar. Modeled quality indicators included biocrude C/H/N contents, higher heating value (HHV), and energy recovery (ER); aqueous total organic carbon (TOC) and total nitrogen (TN) contents; and biochar carbon content. The model was validated with HTL data from the literature, the potential to expand the application of this modeling framework to include waste biosolids (e.g., wastewater sludge, manure) was explored, and future research needs for industrial application were identified. Ultimately, the MCA model represents a critical step towards the integration of cultivation models with downstream HTL and biorefinery operations to enable system-level optimization, valorization of co-product streams (e.g., through catalytic hydrothermal gasification and nutrient recovery), and the navigation of tradeoffs across the value chain.« less

Short-chain chlorinated paraffins in the soils of two different Chinese cities: Occurrence, homologue patterns and vertical migration.

PubMed

Huang, Yumei; Chen, Laiguo; Feng, Yongbin; Ye, Zhixiang; He, Qiusheng; Feng, Qianhua; Qing, Xian; Liu, Ming; Gao, Bo

2016-07-01

Short-chain chlorinated paraffins (SCCPs) are candidate persistent organic pollutants (POPs) that are under review by the Stockholm Convention. China is currently the largest producer and consumer of chlorinated paraffins (CPs). To study the environmental behavior and fate of SCCPs in the soils of urban and suburban regions, the SCCP concentrations in 88 topsoils and 15 soil columns from land of different use types (e.g., woodland, vegetable field, paddy field and greenbelt) from Guangzhou and Chengdu have been determined. The SCCP concentrations in topsoils from Guangzhou (range: 1.45-25.5ngg(-1) dry weight (dw), average: 10.3ngg(-1) dw) were much higher than those from Chengdu (range: 0.218-3.26ngg(-1) dw, average: 1.43ngg(-1) dw). When compared to previously reported SCCP levels for topsoils from other areas, the SCCP concentrations measured in the present work were quite low. Much higher SCCP concentrations were observed in the greenbelt topsoils from Chengdu relative to the values measured from woodlands and vegetable and paddy fields. The composition profiles suggest that C10Cl6-10 and C11-13Cl6-8 were the major groups of SCCPs in topsoils from the woodlands and vegetable and paddy fields in Guangzhou and Chengdu. Vertical variations of the SCCP concentrations in the soil columns suggest that less chlorinated SCCPs (Cl5-6-SCCPs) are more capable of migrating to the deeper-layer soils than more chlorinated ones (Cl9-10-SCCPs). The SCCP concentrations displayed little dependence on organic matter (OM) for most topsoils (p>0.05), indicating that OM is not the controlling factor in the distribution of SCCPs in the soils. This study analyzed the occurrence, homologue patterns and vertical migration of SCCPs in the topsoils of two Chinese cities with different industrial structures and climate conditions. Copyright © 2016 Elsevier B.V. All rights reserved.

Polychlorinated diphenyl ethers (PCDEs) in surface sediments, suspended particulate matter (SPM) and surface water of Chaohu Lake, China.

PubMed

Zhang, Xuesheng; Wang, Tantan; Gao, Lei; Feng, Mingbao; Qin, Li; Shi, Jiaqi; Cheng, Danru

2018-05-31

Polychlorinated diphenyl ethers (PCDEs) are typical halogenated aromatic pollutants that have shown various toxicological effects on organisms. However, the contamination status of PCDEs in the fresh water lakes of China remains poorly researched. In this study, the levels of 15 congeners of PCDEs in the sediments, suspended particulate matter (SPM) and water of Chaohu Lake were determined. The results showed that the ranges of concentrations of total PCDEs (ΣPCDEs) in the sediment, SPM and water were 0.279 ng g -1 dry weight (d.w.)-2.474 ng g -1 d.w., 0.331 ng g -1 d.w.-2.013 ng g -1 d.w. and 0.351 ng L -1 -2.021 ng L -1 , respectively. The most abundant congeners found in sediments, SPM and water were 3,3',4,4'-tetra-CDE, deca-CDE and 2,4,6-tri-CDE, with average contributive ratios of 17.36%, 15.48% and 20.63%, respectively. The medium and higher chlorinated PCDEs (e.g., penta- and deca-CDEs) were the dominant congeners in sediments and SPM. The percentages of lower chlorinated PCDEs (e.g., tri-CDEs) in the water were higher than those in the sediments. The combined input of ΣPCDEs from the eight main tributaries to Chaohu Lake was estimated at 6.94 kg y -1 . Strong linear correlations between the concentrations of ΣPCDEs and organic carbon (OC) contents in three type samples from Chaohu Lake suggested OC could influence the distribution of PCDEs in Chaohu Lake substantially. In addition, the calculated average organic carbon normalized partition coefficients (logK oc ) of 15 PCDEs between water and SPM were in the range of 4.55-5.45 mL g -1 . This study confirmed that Chaohu Lake is contaminated by PCDEs. Copyright © 2018 Elsevier Ltd. All rights reserved.

Hepatoprotective Potential of Chestnut Bee Pollen on Carbon Tetrachloride-Induced Hepatic Damages in Rats

PubMed Central

Yıldız, Oktay; Can, Zehra; Saral, Özlem; Yuluğ, Esin; Öztürk, Ferhat; Aliyazıcıoğlu, Rezzan; Canpolat, Sinan; Kolaylı, Sevgi

2013-01-01

Bee pollen has been used as an apitherapy agent for several centuries to treat burns, wounds, gastrointestinal disorders, and various other diseases. The aim of our study was to investigate the hepatoprotective effects of chestnut bee pollen against carbon tetrachloride (CCI4)-induced liver damage. Total phenolic content, flavonoid, ferric reducing/antioxidant power, and DPPH radical activity measurements were used as antioxidant capacity determinants of the pollen. The study was conducted in rats as seven groups. Two different concentrations of chestnut bee pollens (200 and 400 mg/kg/day) were given orally and one group was administered with silibinin (50 mg/kg/day, i.p.) for seven days to the rats following the CCI4 treatment. The protective effect of the bee pollen was monitored by aspartate transaminase (AST) and alanine transaminase (AST) activities, histopathological imaging, and antioxidant parameters from the blood and liver samples of the rats. The results were compared with the silibinin-treated and untreated groups. We detected that CCI4 treatment induced liver damage and both the bee pollen and silibinin-treated groups reversed the damage; however, silibinin caused significant weight loss and mortality due, severe diarrhea in the rats. The chestnut pollen had showed 28.87 mg GAE/g DW of total phenolic substance, 8.07 mg QUE/g DW of total flavonoid, 92.71 mg Cyn-3-glu/kg DW of total anthocyanins, and 9 mg β-carotene/100 g DW of total carotenoid and substantial amount of antioxidant power according to FRAP and DPPH activity. The results demonstrated that the chestnut bee pollen protects the hepatocytes from the oxidative stress and promotes the healing of the liver damage induced by CCI4 toxicity. Our findings suggest that chestnut bee pollen can be used as a safe alternative to the silibinin in the treatment of liver injuries. PMID:24250716

Double-spin-echo diffusion weighting with a modified eddy current adjustment.

PubMed

Finsterbusch, Jürgen

2010-04-01

Magnetic field inhomogeneities like eddy current-related gradient fields cause geometric distortions in echo-planar imaging (EPI). This in particular affects diffusion-weighted imaging where these distortions vary with the direction of the diffusion weighting and hamper the accurate determination of diffusion parameters. The double-spin-echo preparation often used aims to reduce the cumulative eddy current effect by adjusting the diffusion-weighting gradient pulse durations to the time constant of the dominant eddy current contribution. However, eddy currents with a variety of time constants may be present and cause residual distortions. Here, a modification is proposed where the two bipolar gradient pairs of the preparation are adjusted independently to different time constants. At the expense of a slightly prolonged echo time, residual geometric distortions and correspondingly increased values of the diffusion anisotropy can be reduced as is demonstrated in phantoms and the human brain. Thus, it may help to improve the reliability of diffusion-weighted EPI. Copyright 2010 Elsevier Inc. All rights reserved.

Color stability, radiopacity, and chemical characteristics of white mineral trioxide aggregate associated with 2 different vehicles in contact with blood.

PubMed

Guimarães, Bruno Martini; Tartari, Talita; Marciano, Marina Angélica; Vivan, Rodrigo Ricci; Mondeli, Rafael Francisco Lia; Camilleri, Josette; Duarte, Marco Antonio Hungaro

2015-06-01

Discoloration of mineral trioxide aggregate (MTA) can be exacerbated by the interaction of the cement with body fluids such as blood. This study aimed to analyze the color alteration, chemical characteristics, and radiopacity of MTA manipulated with 2 different vehicles after immersion in blood or distilled water (DW). MTA mixed with 100% DW or 80% DW/20% propylene glycol (PG) as vehicles were placed into rubber rings and incubated at 37°C and 100% relative humidity until set. Color assessment and scanning electron microscopy/energy-dispersive spectroscopy analysis were performed after setting and repeated after 7, 15, and 30 days after immersion in blood and DW. Statistical analysis for color alteration and radiopacity was performed using nonparametric Kruskal-Wallis and Dunn tests (P < .05). When 80% DW/20% PG was used as the vehicle, significantly lower color alterations were observed for all time periods compared with 100% DW when immersed in blood (P < .05). All surfaces displayed morphologic changes after immersion in both media because of loss of bismuth. A decrease in radiopacity was observed over time in all groups, with a statistically significant difference after 30 days for groups DW immersed in blood and 80% DW/20% immersed in both media (P < .05). The ratio of 80% DW/20% PG as a vehicle for MTA results in a lower color alteration when in contact with blood. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Differences in swallow physiology in patients with left and right hemispheric strokes.

PubMed

Wilmskoetter, Janina; Martin-Harris, Bonnie; Pearson, William G; Bonilha, Leonardo; Elm, Jordan J; Horn, Janet; Bonilha, Heather S

2018-05-11

We sought to determine the impact of lesion lateralization and lesion volume on swallow impairment on group-level by comparing patients with left and right hemisphere strokes and on patient-level by analyzing patients individually. We performed a retrospective, observational, cross-sectional study of 46 patients with unilateral (22 left, 24 right), acute, first-ever, ischemic strokes who received a diffusion weighted MRI (DW-MRI) and modified barium swallow study (MBSS) during their acute hospital stay. We determined lesion side on the DW-MRI and measured swallow physiology using the Modified Barium Swallow Impairment Profile (MBSImP™©), Penetration-Aspiration Scale (PAS), swallow timing, distance, area, and speed measures. We performed Pearson's Chi-Square and Wilcoxon Rank-Sum tests to compare patients with left and right hemisphere strokes, and Pearson or Spearman correlation, simple logistic regression, linear, and logistic multivariable regression modeling to assess the relationship between variables. At the group-level, there were no differences in MBSImP oral swallow impairment scores between patients with left and right hemisphere stroke. In adjusted analyses, patients with right hemisphere strokes showed significantly worse MBSImP pharyngeal total scores (p = 0.02), worse MBSImP component specific scores for laryngeal vestibular closure (Bonferroni adjusted alpha p ≤ 0.0029), and worse PAS scores (p = 0.03). Patients with right hemisphere strokes showed worse timing, distance, area, and speed measures. Lesion volume was significantly associated with MBSImP pharyngeal residue (p = 0.03) and pharyngeal total scores (p = 0.04). At the patient-level, 24% of patients (4 left, 7 right) showed opposite patterns of MBSImP oral and pharyngeal swallow impairment than seen at group-level. Our study showed differences in swallow physiology between patients with right and left unilateral strokes with patients with right hemisphere strokes showing worse pharyngeal impairment. Lesion lateralization seems to be a valuable marker for the severity of swallowing impairment at the group-level but less informative at the patient-level. Copyright © 2018 Elsevier Inc. All rights reserved.

Analysis of intracellular and extracellular microcystin variants in sediments and pore waters by accelerated solvent extraction and high performance liquid chromatography-tandem mass spectrometry.

PubMed

Zastepa, Arthur; Pick, Frances R; Blais, Jules M; Saleem, Ammar

2015-05-04

The fate and persistence of microcystin cyanotoxins in aquatic ecosystems remains poorly understood in part due to the lack of analytical methods for microcystins in sediments. Existing methods have been limited to the extraction of a few extracellular microcystins of similar chemistry. We developed a single analytical method, consisting of accelerated solvent extraction, hydrophilic-lipophilic balance solid phase extraction, and reversed phase high performance liquid chromatography-tandem mass spectrometry, suitable for the extraction and quantitation of both intracellular and extracellular cyanotoxins in sediments as well as pore waters. Recoveries of nine microcystins, representing the chemical diversity of microcystins, and nodularin (a marine analogue) ranged between 75 and 98% with one, microcystin-RR (MC-RR), at 50%. Chromatographic separation of these analytes was achieved within 7.5 min and the method detection limits were between 1.1 and 2.5 ng g(-1) dry weight (dw). The robustness of the method was demonstrated on sediment cores collected from seven Canadian lakes of diverse geography and trophic states. Individual microcystin variants reached a maximum concentration of 829 ng g(-1) dw on sediment particles and 132 ng mL(-1) in pore waters and could be detected in sediments as deep as 41 cm (>100 years in age). MC-LR, -RR, and -LA were more often detected while MC-YR, -LY, -LF, and -LW were less common. The analytical method enabled us to estimate sediment-pore water distribution coefficients (K(d)), MC-RR had the highest affinity for sediment particles (log K(d)=1.3) while MC-LA had the lowest affinity (log K(d)=-0.4), partitioning mainly into pore waters. Our findings confirm that sediments serve as a reservoir for microcystins but suggest that some variants may diffuse into overlying water thereby constituting a new route of exposure following the dissipation of toxic blooms. The method is well suited to determine the fate and persistence of different microcystins in aquatic systems. Copyright © 2015 Elsevier B.V. All rights reserved.

Study of geographical trends of polycyclic aromatic hydrocarbons using pine needles

NASA Astrophysics Data System (ADS)

Amigo, José Manuel; Ratola, Nuno; Alves, Arminda

2011-10-01

In this work, pine needles were used as polycyclic aromatic hydrocarbons (PAHs) markers to study the PAHs distribution over several geographical locations in Portugal and over time. Four pine needle sampling campaigns (winter, spring, summer and autumn 2007) were carried out in 29 sites, covering the major urban centres, some industrial points, smaller cities, rural areas and remote locations. Needles from Pinus pinaster Ait. and Pinus pinea L. trees were collected from 2005 and 2006 shoots, corresponding to one up to three years of exposure. Spatial trends of the incidence of PAHs indicate an increase from the remote to the urban and industrial sites. The mean values for the sum of 16 PAHs ranged from 96 ± 30 ng g -1 (dry weight) for remote sites to 866 ± 304 ng g -1 (dw) for industrial sites for P. pinaster needles and from 188 ± 117 ng g -1 (dw) for rural sites to 337 ± 153 ng g -1 (dw) for urban sites for P. pinea. Geographic information system tools and principal component analysis revealed that the contamination patterns of PAHs are somehow related to several socio-geographic parameters of the sampling sites. The geographical trend for the PAHs is similar between seasons in terms of PAH levels, but some diverse behaviour is found on the separation of lighter and heavier PAHs. Differences between P. pinaster and P. pinea needles are stronger in terms of PAH uptake loads than in the site type fingerprints.

[Reproductive effort, fattening index and yield of Arca zebra (Filibranchia: Arcidae) by length and its association with environmental variables, Sucre, Venezuela].

PubMed

Lista, María; Velásquez, Carlos; Prieto, Antulio; Longart, Yelipza

2016-06-01

Arca zebra is a mollusk of commercial value and a major socioeconomic fishery in Northeastern Venezuela. The present study aimed to evaluate the reproductive effort (RE), fattening index (FI) and yield (Y) in different size groups of A. zebra from the morro Chacopata, Venezuela. For this, monthly samplings from June 2008 and June 2009, were undertaken, and the bivalves obtained were distributed in three length groups: I (30.1 to 50.0 mm), II (50.1 to 70.0 mm) and III (> 70.0 mm). Monthly RE, FI and Y were determined based on bivalve changes in volume of fresh meat (VFM), intervalvar volume (IV), dry gonad biomass (DW), dry biomass of the organism without gonad (DWs), fresh biomass of meat (FBM) and total biomass including shell (TBIS). Besides, environmental variables such as temperature, salinity, dissolved oxygen, total organic and inorganic seston and chlorophyll a were measured monthly. There was great variation in the DW between length groups (relevant for II and III): increased from June until late September 2008, was followed by a marked decrease in October 2008, recovered in the following months, and decreased in January 2009, with a slight increase until May 2009; these changes were associated with variations in sea temperature. The weight of the gonad (DW) influenced the RE, FI and Y, as these reached their peaks in the months where there was higher gonadal production, indicating the influence of temperature on A. zebra reproduction.

Distribution and preliminary exposure assessment of bisphenol AF (BPAF) in various environmental matrices around a manufacturing plant in China.

PubMed

Song, Shanjun; Ruan, Ting; Wang, Thanh; Liu, Runzeng; Jiang, Guibin

2012-12-18

Increasing attention has been paid to bisphenol A and bisphenol (BP) analogues due to high production volumes, wide usage and potential adverse effects. Bisphenol AF (BPAF) is considered a new bisphenol analogue which is used as raw material in plastic industry, but little is known about its occurrence in the environment and the potential associated risk. In this work, BPAF levels and environmental distribution were reported in samples collected around a manufacturing plant and a preliminary exposure risk assessment to local residents was conducted. BPAF was detected in most of the samples, with levels in river ranging between

Persistent Organic Pollutants in sediment and fish in the River Thames Catchment (UK).

PubMed

Lu, Qiong; Jürgens, Monika D; Johnson, Andrew C; Graf, Carola; Sweetman, Andy; Crosse, John; Whitehead, Paul

2017-01-15

Some organic pollutants including polychlorinated biphenyls (PCBs), polybrominated diphenylethers (PBDEs) and hexachlorobenzene (HCB) have been banned from production and use in the UK for >30years but due to their toxicity and persistence are still of concern. However, due to their hydrophobicity they are present at very low concentrations and are difficult to measure in water, and so other matrices need to be sampled in order to best assess contamination. This study measured concentrations of ΣICES 7 PCBs (PCB congeners 28, 52, 101, 118, 138, 153 and 180) and Σ6 PBDEs (PBDE congeners 28, 47, 99, 100, 153, 154) and HCB in both bed-sediments and wild roach (a common pelagic fish) in the Thames Basin. The highest sediment concentrations were detected in an urbanised tributary of the Thames, The Cut at Bracknell (HCB: 0.03-0.40μg/kg dw; ICES 7 PCBs: 4.83-7.42μg/kg dw; 6 BDEs: 5.82-23.10μg/kg dw). When concentrations were expressed on a dry weight basis, the fish were much more contaminated than the sediments, but when sediment concentrations were normalised to organic carbon concentration they were comparable to the fish lipid normalised concentrations. Thus, despite the variability in the system, both sediments and wild fish can be considered suitable for representing the level of POPs contamination of the river system given sufficient sample numbers. Copyright © 2016 Elsevier B.V. All rights reserved.

Ultrasound-Assisted Extraction and Identification of Natural Antioxidants from the Fruit of Melastoma sanguineum Sims.

PubMed

Zhou, Tong; Xu, Dong-Ping; Lin, Sheng-Jun; Li, Ya; Zheng, Jie; Zhou, Yue; Zhang, Jiao-Jiao; Li, Hua-Bin

2017-02-18

The fruit of Melastoma sanguineum Sims is an edible and sweet wild fruit. In our previous study, the fruit was found to have a strong antioxidant property. In this study, an ultrasound-assisted extraction (UAE) method was developed to extract natural antioxidants from the fruit of Melastoma sanguineum Sims, and a response surface methodology was used to optimize the conditions of UAE to maximize the extraction efficiency. The influence of five independent extraction parameters (ethanol concentration, solvent/material ratio, extracting time, temperature, and ultrasound power) on the extraction efficiency were investigated using a single factor experiment, and then a central composite rotatable design was used to investigate the interaction of three key parameters. The results showed that the optimal extraction conditions were 42.98% ethanol, 28.29 mL/g solvent/material ratio, 34.29 min extracting time, 60 °C temperature, and 600 W ultrasound power. Under these conditions, the Trolox equivalent antioxidant capacity (TEAC) value of the extracts was 1074.61 ± 32.56 μmol Trolox/g dry weight (DW). Compared with conventional maceration (723.27 ± 11.61 μmol Trolox/g DW) and Soxhlet extraction methods (518.37 ± 23.23 μmol Trolox/g DW), the UAE method improved the extraction efficiency, in a shorter period of time. In addition, epicatechin gallate, epicatechin, rutin, epigallocatechin, protocatechuic acid, chlorogenic acid, and quercetin, were identified and quantified in the fruit extracts of Melastoma sanguineum Sims by UPLC-MS/MS.

National surveillance of 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins/furans in soil in Taiwan.

PubMed

Hsu, Yi-Chyun; Que, Danielle E; Gou, Yan-You; Tsou, Tsui-Chun; Liu, Chung-Kun; Wang, Yen-Ling; Hou, Wen-Che; Lin, Yi-Hsien; Liu, Wen-Yao; Chao, How-Ran; Lee, Wen-Jhy

2018-07-01

In this study, the polychlorinated dibenzo-p-dioxin/furan (PCDD/F) levels in 381 soil samples coming from different background areas (n = 238) and contaminated areas (n = 143) in Taiwan were investigated from 2011 to 2015 using high resolution gas chromatograph/high resolution mass spectrometry (HRGC/HRMS). The contaminated areas showed higher PCDD/F contamination as compared to the background areas (1230 vs 749 pg/g dry weight (dw)); 14.0 vs 6.25 pg WHO 2005 -TEQ/g dw). The lowest levels were recorded in the outlying islands (1.28 pg WHO 2005 -TEQ/g dw). PCDD/F congener distribution profiles in the background and contaminated areas as well as on the islands varied. OCDD was the dominant congener in almost all locations, including the northern background (87.7%) and central contaminated (74.2%) areas. Other dominant species included OCDF and 1,2,3,4,6,7,8-HpCDD. Levels of PCDD/F-TEQs in Taiwanese soils, including the background areas, were higher than in some developing countries and regions with global background levels due to high industrialization except for the contaminated areas. Geographic differences in dioxin-contaminated soils were also shown in this study. Higher soil dioxin-TEQs were observed in locations with high populations and population densities. Despite the limitations, the economic status of Taiwan represented by the annual averaged family income (AAFI) was positively correlated to soil dioxin-TEQs. Copyright © 2018. Published by Elsevier Ltd.

Evaluation of tobacco (Nicotiana tabacum L. cv. Petit Havana SR1) hairy roots for the production of geraniol, the first committed step in terpenoid indole alkaloid pathway.

PubMed

Ritala, Anneli; Dong, Lemeng; Imseng, Nicole; Seppänen-Laakso, Tuulikki; Vasilev, Nikolay; van der Krol, Sander; Rischer, Heiko; Maaheimo, Hannu; Virkki, Arho; Brändli, Johanna; Schillberg, Stefan; Eibl, Regine; Bouwmeester, Harro; Oksman-Caldentey, Kirsi-Marja

2014-04-20

The terpenoid indole alkaloids are one of the major classes of plant-derived natural products and are well known for their many applications in the pharmaceutical, fragrance and cosmetics industries. Hairy root cultures are useful for the production of plant secondary metabolites because of their genetic and biochemical stability and their rapid growth in hormone-free media. Tobacco (Nicotiana tabacum L. cv. Petit Havana SR1) hairy roots, which do not produce geraniol naturally, were engineered to express a plastid-targeted geraniol synthase gene originally isolated from Valeriana officinalis L. (VoGES). A SPME-GC-MS screening tool was developed for the rapid evaluation of production clones. The GC-MS analysis revealed that the free geraniol content in 20 hairy root clones expressing VoGES was an average of 13.7 μg/g dry weight (DW) and a maximum of 31.3 μg/g DW. More detailed metabolic analysis revealed that geraniol derivatives were present in six major glycoside forms, namely the hexose and/or pentose conjugates of geraniol and hydroxygeraniol, resulting in total geraniol levels of up to 204.3 μg/g DW following deglycosylation. A benchtop-scale process was developed in a 20-L wave-mixed bioreactor eventually yielding hundreds of grams of biomass and milligram quantities of geraniol per cultivation bag. Copyright © 2014 Elsevier B.V. All rights reserved.

Massive shelf dense water flow influences plankton community structure and particle transport over long distance.

PubMed

Bernardi Aubry, Fabrizio; Falcieri, Francesco Marcello; Chiggiato, Jacopo; Boldrin, Alfredo; Luna, Gian Marco; Finotto, Stefania; Camatti, Elisa; Acri, Francesco; Sclavo, Mauro; Carniel, Sandro; Bongiorni, Lucia

2018-03-14

Dense waters (DW) formation in shelf areas and their cascading off the shelf break play a major role in ventilating deep waters, thus potentially affecting ecosystem functioning and biogeochemical cycles. However, whether DW flow across shelves may affect the composition and structure of plankton communities down to the seafloor and the particles transport over long distances has not been fully investigated. Following the 2012 north Adriatic Sea cold outbreak, DW masses were intercepted at ca. 460 km south the area of origin and compared to resident ones in term of plankton biomass partitioning (pico to micro size) and phytoplankton species composition. Results indicated a relatively higher contribution of heterotrophs in DW than in deep resident water masses, probably as result of DW-mediated advection of fresh organic matter available to consumers. DWs showed unusual high abundances of Skeletonema sp., a diatom that bloomed in the north Adriatic during DW formation. The Lagrangian numerical model set up on this diatom confirmed that DW flow could be an important mechanism for plankton/particles export to deep waters. We conclude that the predicted climate-induced variability in DW formation events could have the potential to affect the ecosystem functioning of the deeper part of the Mediterranean basin, even at significant distance from generation sites.

The Effects of Data Collection Method and Monitoring of Workers’ Behavior on the Generation of Demolition Waste

PubMed Central

Cha, Gi-Wook; Kim, Young-Chan; Moon, Hyeun Jun; Hong, Won-Hwa

2017-01-01

The roles of both the data collection method (including proper classification) and the behavior of workers on the generation of demolition waste (DW) are important. By analyzing the effect of the data collection method used to estimate DW, and by investigating how workers’ behavior can affect the total amount of DW generated during an actual demolition process, it was possible to identify strategies that could improve the prediction of DW. Therefore, this study surveyed demolition waste generation rates (DWGRs) for different types of building by conducting on-site surveys immediately before demolition in order to collect adequate and reliable data. In addition, the effects of DW management strategies and of monitoring the behavior of workers on the actual generation of DW were analyzed. The results showed that when monitoring was implemented, the estimates of DW obtained from the DWGRs that were surveyed immediately before demolition and the actual quantities of DW reported by the demolition contractors had an error rate of 0.63% when the results were compared. Therefore, this study has shown that the proper data collection method (i.e., data were collected immediately before demolition) applied in this paper and monitoring on the demolition site have a significant impact on waste generation. PMID:29023378

Methodological Guidelines for Reducing the Complexity of Data Warehouse Development for Transactional Blood Bank Systems

PubMed Central

Takecian, Pedro L.; Oikawa, Marcio K.; Braghetto, Kelly R.; Rocha, Paulo; Lucena, Fred; Kavounis, Katherine; Schlumpf, Karen S.; Acker, Susan; Carneiro-Proietti, Anna B. F.; Sabino, Ester C.; Custer, Brian; Busch, Michael P.; Ferreira, João E.

2013-01-01

Over time, data warehouse (DW) systems have become more difficult to develop because of the growing heterogeneity of data sources. Despite advances in research and technology, DW projects are still too slow for pragmatic results to be generated. Here, we address the following question: how can the complexity of DW development for integration of heterogeneous transactional information systems be reduced? To answer this, we proposed methodological guidelines based on cycles of conceptual modeling and data analysis, to drive construction of a modular DW system. These guidelines were applied to the blood donation domain, successfully reducing the complexity of DW development. PMID:23729945

Methodological Guidelines for Reducing the Complexity of Data Warehouse Development for Transactional Blood Bank Systems.

PubMed

Takecian, Pedro L; Oikawa, Marcio K; Braghetto, Kelly R; Rocha, Paulo; Lucena, Fred; Kavounis, Katherine; Schlumpf, Karen S; Acker, Susan; Carneiro-Proietti, Anna B F; Sabino, Ester C; Custer, Brian; Busch, Michael P; Ferreira, João E

2013-06-01

Over time, data warehouse (DW) systems have become more difficult to develop because of the growing heterogeneity of data sources. Despite advances in research and technology, DW projects are still too slow for pragmatic results to be generated. Here, we address the following question: how can the complexity of DW development for integration of heterogeneous transactional information systems be reduced? To answer this, we proposed methodological guidelines based on cycles of conceptual modeling and data analysis, to drive construction of a modular DW system. These guidelines were applied to the blood donation domain, successfully reducing the complexity of DW development.

Microalgal mediation of ripple mobility.

PubMed

Friend, P L; Lucas, C H; Holligan, P M; Collins, M B

2008-01-01

The interaction between physical and biological factors responsible for the cessation of ripple migration on a sandy intertidal flat was examined during a microalgal bloom period in late winter/early spring, as part of a wider study into the biostabilisation of intertidal sediments. Ripple positions and ripple geometry were monitored, and surface sediment was sampled, at weekly intervals over a 5-week period. Ripples remained in the same position for at least 4 weeks, during which time there was a progressive reduction in bedform height (smoothing) and deposition of some 1.5 cm sediment, mainly in the ripple troughs (surface levelling). The mean chlorophyll a (chl a) sediment content was 6.0 microg gDW(-1) (DW: dry weight) (0-1 mm depth fraction), with a maximum value of 7.4 microg gDW(-1) half way through the bloom. Mean colloidal-S carbohydrate (S: saline extraction) content was 131 microg GE gDW(-1) (GE: glucose equivalent) (0-1 mm), with a maximum of 261 microg GE gDW(-1 )towards the end of the bloom. Important accessory pigments were peridinin (indicative of dinophytes) and fucoxanthin (diatoms). Stepwise multiple regression showed that peridinin was the best predictor of chl a. For the first time, in situ evidence for the mediation of (wave) ripple migration by microalgae is provided. Results indicate that diatoms, and quite possibly dinophytes, can have a significant effect on intertidal flat ripple mobility on a temporal scale of weeks. In addition, microalgal effects appear capable of effecting a reduction in bed roughness on a spatial scale of up to 10(-2 )m, with a subsequent reduction in bottom stress and bed erodability. It is suggested that a unique combination of environmental conditions, in conjunction with the microalgal bloom(s), promoted the initial cessation of ripple movement, and that stationary-phase, diatom-derived extracellular polymeric substances (EPS) (and possibly dinophyte-derived EPS) may have prolonged the condition. It is reasonable to suppose that ripple stabilisation by similar processes may have contributed to ripple mark preservation in the geological record. A conceptual model of sandy intertidal flat processes is presented, illustrating two conditions: (i) a low EPS/microalgae sediment content with low ripple stabilisation and preservation potential; and (ii) a high EPS/microalgae content with higher preservation potential.

Polymer/reduced graphene oxide functionalized sponges as superabsorbents for oil removal and recovery.

PubMed

Periasamy, Arun Prakash; Wu, Wen-Ping; Ravindranath, Rini; Roy, Prathik; Lin, Guan-Lin; Chang, Huan-Tsung

2017-01-30

Polyurethane dish-washing (PU-DW) sponges are functionalized sequentially with polyethylenimine (PEI) and graphene oxide (GO) to form PEI/reduced graphene oxide (RGO) PU-DW sponges. The PEI/RGO PU-DW sponge consists of PEI/RGO sheets having numerous pores, with diameters ranging from 236 to 254nm. To further enhance hydrophobicity and absorption capacity of oil, PEI/RGO PU-DW sponge is further coated with 20% phenyltrimethoxysilane (PTMOS). The PTMOS/PEI/RGO PU-DW sponge absorbs various oils within 20s, with maximum absorption capacity values of 880% and 840% for bicycle chain oil and motorcycle engine oil, respectively. The absorbed oils were released completely by squeezing or immersed in hexane. The PTMOS/PEI/RGO PU-DW sponge efficiently separates oil/water mixtures through a flowing system. Having the advantages of faster absorption rate, reusability, and low cost, the PTMOS/PEI/RGO PU-DW sponge holds great potential as a superabsorbent for efficient removal and recovery of oil spills as well as for the separation of oil/water mixtures. Copyright © 2016 Elsevier Ltd. All rights reserved.

Accumulation of arsenic by aquatic plants in large-scale field conditions: opportunities for phytoremediation and bioindication.

PubMed

Favas, Paulo J C; Pratas, João; Prasad, M N V

2012-09-01

This work focuses on the potential of aquatic plants for bioindication and/or phytofiltration of arsenic from contaminated water. More than 71 species of aquatic plants were collected at 200 sampling points in running waters. The results for the 18 most representative plant species are presented here. The species Ranunculus trichophyllus, Ranunculus peltatus subsp. saniculifolius, Lemna minor, Azolla caroliniana and the leaves of Juncus effusus showed a very highly significant (P<0.001) positive correlation with the presence of arsenic in the water. These species may serve as arsenic indicators. The highest concentration of arsenic was found in Callitriche lusitanica (2346 mg/kg DW), Callitriche brutia (523 mg/kg DW), L. minor (430 mg/kg DW), A. caroliniana (397 mg/kg DW), R. trichophyllus (354 mg/kg DW), Callitriche stagnalis (354 mg/kg DW) and Fontinalis antipyretica (346 mg/kg DW). These results indicate the potential application of these species for phytofiltration of arsenic through constructed treatment wetlands or introduction of these plant species into natural water bodies. Copyright © 2012 Elsevier B.V. All rights reserved.

Effect of inoculation with Penicillium expansum on the microbial community and maturity of compost.

PubMed

Wang, Hong-yuan; Fan, Bing-quan; Hu, Qing-xiu; Yin, Zhong-wei

2011-12-01

Compost prepared from wheat straw and cattle/chicken mature was inoculated with the lignocellulolytic fungus, Penicillium expansum. Compared to uninoculated compost, the inoculated compost exhibited a 150% higher germination index, more than 1.2 g kg(-1)-dw of changes in NH(4)(+)-N concentrations, a ca. 12.0% higher humus content and a lignocellulose degradation that proceeded 57.5% faster. Culture-based determinations of microbial populations demonstrated that aerobic heterotrophic bacteria and fungi were about 1-2 orders of magnitude higher in inoculated than in uninoculated compost. The number of ammonifying, ammonium-oxidizing, nitrite-oxidizing, denitrifying bacteria and cellulose-decomposing bacteria was 6.1-9.0 log(10) CFU g(-1)-dw, 1.2-4.3 log(10) MPN g(-1)-dw, 3.5-6.8 log(10) MPN g(-1)-dw, 3.58-4.34 log(10) MPN g(-1)-dw, 1.4-3.8 log(10)MPN g(-1)-dw, and 4.2-8.8 log(10) CFU g(-1)-dw higher in the compost inoculated with P. expansum. Copyright © 2011 Elsevier Ltd. All rights reserved.

Separation of extra- and intracellular metabolites using hyperpolarized 13C diffusion weighted MR

NASA Astrophysics Data System (ADS)

Koelsch, Bertram L.; Sriram, Renuka; Keshari, Kayvan R.; Leon Swisher, Christine; Van Criekinge, Mark; Sukumar, Subramaniam; Vigneron, Daniel B.; Wang, Zhen J.; Larson, Peder E. Z.; Kurhanewicz, John

2016-09-01

This work demonstrates the separation of extra- and intracellular components of glycolytic metabolites with diffusion weighted hyperpolarized 13C magnetic resonance spectroscopy. Using b-values of up to 15,000 s mm-2, a multi-exponential signal response was measured for hyperpolarized [1-13C] pyruvate and lactate. By fitting the fast and slow asymptotes of these curves, their extra- and intracellular weighted diffusion coefficients were determined in cells perfused in a MR compatible bioreactor. In addition to measuring intracellular weighted diffusion, extra- and intracellular weighted hyperpolarized 13C metabolites pools are assessed in real-time, including their modulation with inhibition of monocarboxylate transporters. These studies demonstrate the ability to simultaneously assess membrane transport in addition to enzymatic activity with the use of diffusion weighted hyperpolarized 13C MR. This technique could be an indispensible tool to evaluate the impact of microenvironment on the presence, aggressiveness and metastatic potential of a variety of cancers.

Direct Observation of Domain-Wall Surface Tension by Deflating or Inflating a Magnetic Bubble

NASA Astrophysics Data System (ADS)

Zhang, Xueying; Vernier, Nicolas; Zhao, Weisheng; Yu, Haiming; Vila, Laurent; Zhang, Yue; Ravelosona, Dafiné

2018-02-01

The surface energy of a magnetic domain wall (DW) strongly affects its static and dynamic behaviors. However, this effect is seldom directly observed, and some of the related phenomena are not well understood. Moreover, a reliable method to quantify the DW surface energy is still absent. Here, we report a series of experiments in which the DW surface energy becomes a dominant parameter. We observe that a semicircular magnetic domain bubble can spontaneously collapse under the Laplace pressure induced by DW surface energy. We further demonstrate that the surface energy can lead to a geometrically induced pinning when the DW propagates in a Hall cross or from a nanowire into a nucleation pad. Based on these observations, we develop two methods to quantify the DW surface energy, which can be very helpful in the estimation of intrinsic parameters such as Dzyaloshinskii-Moriya interactions or exchange stiffness in magnetic ultrathin films.

Profiling of phenolic compounds and their antioxidant and anticancer activities in pandan (Pandanus amaryllifolius Roxb.) extracts from different locations of Malaysia

PubMed Central

2013-01-01

Background Phytochemicals and antioxidants from plant sources are of increasing interest to consumers because of their roles in the maintenance of human health. Most of the secondary metabolites of herbs are used in a number of pharmaceutical products. Methods Secondary metabolites composition and content of five flavonoids and three phenolic acids were evaluated and determined in Pandanus amaryllifolius extracts from three different locations of Malaysia by RP-HPLC; Total phenolic and total flavonoid content were determined using Folin-Ciocalteau and aluminum chloride colorimetric assay; The antioxidant activity of the extracts was determined by the ferric reducing antioxidant potential (FRAP) assay and 1,1-diphenyl-2-picrylhydrazyl (DPPH) assays. MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) Assay was employed to screen anticancer activity of extracts against MCF-7 cancer cell line. Results Highest value of total flavonoids (TF) and total phenolics (TP) was observed in pandan extract from Bachok locattion (1.87 mg/g DW and 6.72 mg/g DW) followed by Klang (1.32 mg/g DW; 5.07 mg/g DW) and Pontian (1.12 mg/g DW; 4.88 mg/g DW). Rutin just detected from Bachok location with value of 0.082 mg/g DW. High content of epicatechin (0.035 mg/g DW) and naringin (0.325 mg/g DW) were observed from Bachok location while, highest content of catechin (0.613 mg/g DW) and kaempferol (0.278 mg/g DW) was observed in pandan extract from Klang location. The extract of pandan from Bachok exhibited highest value of gallic acid (0.423 mg/g DW) and cinnamic acid (0.084 mg/g DW). Ferrulic acid just detected from pandan extract of Bachok location with concentration of 0.281mg/g DW. Between studied locations Bachok exhibited highest value of DPPH (64.27%) and FRAP (517.2 μm of Fe (II)/g) activity followed by Klang (52.16%; 448.6 μm of Fe (II)/g) and Pontian (50.10%; 314.8 μm of Fe (II)/g). The preliminary screening showed pandan extracts from 3 locations possessed anticancer promoting activity against MCF-7 cell line, with 78.3%, 70.5% and 67.4% inhibition rate, respectively. Maximum MCF-7cell line inhibition was observed in pandan extract from Bachok location. Conclusions The samples collected from the North (Bachok) exhibited the highest TP, TF antioxidant and anticancer activity while those from the Southern portion (Pontian) appeared to have the lowest content of TP, TF and antioxidant activity. PMID:24289290

Effects of molecular weight on the diffusion coefficient of aquatic dissolved organic matter and humic substances.

PubMed

Balch, J; Guéguen, C

2015-01-01

In situ measurements of labile metal species using diffusive gradients in thin films (DGT) passive samplers are based on the diffusion rates of individual species. Although most studies have dealt with chemically isolated humic substances, the diffusion of dissolved organic matter (DOM) across the hydrogel is not well understood. In this study, the diffusion coefficient (D) and molecular weight (MW) of 11 aquatic DOM and 4 humic substances (HS) were determined. Natural, unaltered aquatic DOM was capable of diffusing across the diffusive gel membrane with D values ranging from 2.48×10(-6) to 5.31×10(-6) cm(2) s(-1). Humic substances had diffusion coefficient values ranging from 3.48×10(-6) to 6.05×10(-6) cm(2) s(-1), congruent with previous studies. Molecular weight of aquatic DOM and HS samples (∼500-1750 Da) measured using asymmetrical flow field-flow fractionation (AF4) strongly influenced D, with larger molecular weight DOM having lower D values. No noticeable changes in DOM size properties were observed during the diffusion process, suggesting that DOM remains intact following diffusion across the diffusive gel. The influence of molecular weight on DOM mobility will assist in further understanding and development of the DGT technique and the uptake and mobility of contaminants associated with DOM in aquatic environments. Copyright © 2014 Elsevier Ltd. All rights reserved.

Modeling the relationship between body weight and energy intake: A molecular diffusion-based approach

PubMed Central

2012-01-01

Background Body weight is at least partly controlled by the choices made by a human in response to external stimuli. Changes in body weight are mainly caused by energy intake. By analyzing the mechanisms involved in food intake, we considered that molecular diffusion plays an important role in body weight changes. We propose a model based on Fick's second law of diffusion to simulate the relationship between energy intake and body weight. Results This model was applied to food intake and body weight data recorded in humans; the model showed a good fit to the experimental data. This model was also effective in predicting future body weight. Conclusions In conclusion, this model based on molecular diffusion provides a new insight into the body weight mechanisms. Reviewers This article was reviewed by Dr. Cabral Balreira (nominated by Dr. Peter Olofsson), Prof. Yang Kuang and Dr. Chao Chen. PMID:22742862

Pilot Study of the Use of Hybrid Multidimensional T2-Weighted Imaging-DWI for the Diagnosis of Prostate Cancer and Evaluation of Gleason Score.

PubMed

Sadinski, Meredith; Karczmar, Gregory; Peng, Yahui; Wang, Shiyang; Jiang, Yulei; Medved, Milica; Yousuf, Ambereen; Antic, Tatjana; Oto, Aytekin

2016-09-01

The objective of our study was to evaluate the role of a hybrid T2-weighted imaging-DWI sequence for prostate cancer diagnosis and differentiation of aggressive prostate cancer from nonaggressive prostate cancer. Twenty-one patients with prostate cancer who underwent preoperative 3-T MRI and prostatectomy were included in this study. Patients underwent a hybrid T2-weighted imaging-DWI examination consisting of DW images acquired with TEs of 47, 75, and 100 ms and b values of 0 and 750 s/mm(2). The apparent diffusion coefficient (ADC) and T2 were calculated for cancer and normal prostate ROIs at each TE and b value. Changes in ADC and T2 as a function of increasing the TE and b value, respectively, were analyzed. A new metric termed "PQ4" was defined as the percentage of voxels within an ROI that has increasing T2 with increasing b value and has decreasing ADC with increasing TE. ADC values were significantly higher in normal ROIs than in cancer ROIs at all TEs (p < 0.0001). With increasing TE, the mean ADC increased 3% in cancer ROIs and increased 12% in normal ROIs. T2 was significantly higher in normal ROIs than in cancer ROIs at both b values (p ≤ 0.0002). The mean T2 decreased with increasing b value in cancer ROIs (ΔT2 = -17 ms) and normal ROIs (ΔT2 = -52 ms). PQ4 clearly differentiated normal ROIs from prostate cancer ROIs (p = 0.0004) and showed significant correlation with Gleason score (ρ = 0.508, p < 0.0001). Hybrid MRI measures the response of ADC and T2 to changing TEs and b values, respectively. This approach shows promise for detecting prostate cancer and determining its aggressiveness noninvasively.

Current induced domain wall dynamics in the presence of spin orbit torques

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boulle, O., E-mail: Olivier.boulle@cea.fr; Buda-Prejbeanu, L. D.; Jué, E.

2014-05-07

Current induced domain wall (DW) motion in perpendicularly magnetized nanostripes in the presence of spin orbit torques is studied. We show using micromagnetic simulations that the direction of the current induced DW motion and the associated DW velocity depend on the relative values of the field like torque (FLT) and the Slonczewski like torques (SLT). The results are well explained by a collective coordinate model which is used to draw a phase diagram of the DW dynamics as a function of the FLT and the SLT. We show that a large increase in the DW velocity can be reached bymore » a proper tuning of both torques.« less

Immigration Policies in Europe: Impact on Crime -- A Case Study of Germany

DTIC Science & Technology

2008-06-01

2180188,00.html? maca =en-bulletin- 433-html. Accessed 24 Feb 2008. 51 448,000 illegal immigrants up until September 2006 without EU assistance.168 The...asylum. 168 Your Link to Germany. http://www.dw-world.de/dw/article/0,,2180188,00.html? maca =en...for a European Response to Illegal Immigration" 21 September 2006. .http://www.dw- world.de/dw/article/0,,2180188,00.html? maca =en-bulletin-433-html

Wettability Patterning for Enhanced Dropwise Condensation

NASA Astrophysics Data System (ADS)

Ghosh, Aritra; Ganguly, Ranjan; Megaridis, Constantine

2014-11-01

Dropwise condensation (DwC), in order to be sustainable, requires removal of the condensate droplets. This removal is frequently facilitated by gravity. The rate of DwC heat transfer depends strongly on the maximum departing droplet diameter. Based on wettability patterning, we present a facile technique designed to control the maximum droplet size in DwC within vapor/air atmospheres, and demonstrate how this approach can be used to enhance the corresponding heat transfer rate. We examine various hydrophilic-superhydrophilic patterns, which, respectively sustain DwC and filmwise (FwC) condensation on the substrate. The fabrication method does notemploy any hydrophobizing agent. By juxtaposing parallel lines of hydrophilic (CA ~ 78°) and superhydrophilic (CA ~ 0°) regions on the condensing surface, we create alternating domains of DwC and FwC. The average droplet size on the DwC domain is reduced by ~ 60% compared to the theoretical maximum, which corresponds to the line width. We compare heat transfer rate between unpatternend DwC surfaces and patterned DwC surfaces. Even after sacrificing 40% of condensing area, we achieve up to 20% improvement in condensate collection rate using an interdigitated superhydrophilic pattern, inspired by the vein network of plant leaves. The bioinspired interdigitated pattern is found to outperform the straight hydrophilic-superhydrophilic pattern, particularly under higher vapor loadings in an air/vapor ambient atmosphere. NSF STTR Grant 1331817 via NBD Nano.

Optimization of narrow width effect on titanium thermistor in uncooled antenna-coupled terahertz microbolometer

NASA Astrophysics Data System (ADS)

Banerjee, Amit; Satoh, Hiroaki; Elamaran, Durgadevi; Sharma, Yash; Hiromoto, Norihisa; Inokawa, Hiroshi

2018-04-01

Uncooled antenna-coupled terahertz microbolometer arrays are fabricated with a meander-type Ti thermistor, and design widths (DW) = 0.1 and 0.2 µm, considering the design requirement to miniaturize detectors. Each unit device with DW = 0.1 µm of the thermistor has about 4.7 time higher electrical responsivity (132 V/W) than that with DW = 0.2 µm (28.2 V/W) at 10 µA bias current. For DW = 0.2 µm, the calculated noise equivalent power (NEP) was 2.29 × 10‑9 W/\\sqrt{\\text{Hz}} , whereas the minimum NEP of 4.43 × 10‑10 W/\\sqrt{\\text{Hz}} was obtained for DW = 0.1 µm devices, both at 10 µA bias current. The bulk value of temperature coefficient of resistance (TCR) of the Ti thermistor is markedly compromised in low dimensional devices, still in terms of responsivity and NEP, unit devices with Ti thermistor with the lower DW shows better performance. This is because the narrow width effect is minimized owing to higher resistivity for DW = 0.1 than that for DW = 0.2 µm. In this current report, we highlights the optimization of the narrow width effect on TCR of metal interconnects in nanometer dimensions, which to the best of our knowledge is not available at present.

Accuracy of magnetic resonance imaging in differentiating between benign and malignant vertebral lesions: role of diffusion-weighted imaging, in-phase/opposed-phase imaging and apparent diffusion coefficient.

PubMed

Martel Villagrán, J; Bueno Horcajadas, Á; Pérez Fernández, E; Martín Martín, S

2015-01-01

To determine the ability of MRI to distinguish between benign and malignant vertebral lesions. We included 85 patients and studied a total of 213 vertebrae (both pathologic and normal). For each vertebra, we determined whether the lesion was hypointense in T1-weighted sequences and whether it was hyperintense in STIR and in diffusion-weighted sequences. We calculated the in-phase/out-of-phase quotient and the apparent diffusion coefficient for each vertebra. We combined parameters from T1-weighted, diffusion-weighted, and STIR sequences to devise a formula to distinguish benign from malignant lesions. The group comprised 60 (70.6%) women and 25 (29.4%) men with a mean age of 67±13.5 years (range, 33-90 y). Of the 85 patients, 26 (30.6%) had a known primary tumor. When the lesion was hypointense on T1-weighted sequences, hyperintense on STIR and diffusion-weighted sequences, and had a signal intensity quotient greater than 0.8, the sensitivity was 97.2%, the specificity was 90%, and the diagnostic accuracy was 91.2%. If the patient had a known primary tumor, these values increased to 97.2%, 99.4%, and 99%, respectively. Benign lesions can be distinguished from malignant lesions if we combine the information from T1-weighted, STIR, and diffusion-weighted sequences together with the in-phase/out-of-phase quotient of the lesion detected in the vertebral body on MRI. Copyright © 2013 SERAM. Published by Elsevier España, S.L.U. All rights reserved.

The Effects of Metal on Size Specific Dose Estimation (SSDE) in CT: A Phantom Study

NASA Astrophysics Data System (ADS)

Alsanea, Maram M.

Over the past number of years there has been a significant increase in the awareness of radiation dose from use of computed tomography (CT). Efforts have been made to reduce radiation dose from CT and to better quantify dose being delivered. However, unfortunately, these dose metrics such as CTDI vol are not a specific patient dose. In 2011, the size-specific dose estimation (SSDE) was introduced by AAPM TG-204 which accounts for the physical size of the patient. However, the approach presented in TG-204 ignores the importance of the attenuation differences in the body. In 2014, a newer methodology that accounted for tissue attenuation was introduced by the AAPM TG-220 based on the concept of water equivalent diameter, Dw. One of the limitation of TG-220 is that there is no estimation of the dose while highly attenuating objects such as metal is present in the body. The purpose of this research is to evaluate the accuracy of size-specific dose estimates in CT in the presence of simulated metal prostheses using a conventional PMMA CTDI phantom at different phantom diameter (body and head) and beam energy. Titanium, Cobalt- chromium and stainless steel alloys rods were used in the study. Two approaches were used as introduced by AAPM TG-204 and 220 utilizing the effective diameter and the Dw calculations. From these calculations, conversion factors have been derived that could be applied to the measured CTDIvol to convert it to specific patient dose, or size specific dose estimate, (SSDE). Radiation dose in tissue (f-factor = 0.94) was measured at various chamber positions with the presence of metal. Following, an average weighted tissue dose (AWTD) was calculated in a manner similar to the weighted CTDI (CTDIw). In general, for the 32 cm body phantom SSDE220 provided more accurate estimates of AWTD than did SSDE204. For smaller patient size, represented by the 16 cm head phantom, the SSDE204 was a more accurate estimate of AWTD that that of SSDE220. However, as the quantity of metal increased it was shown that SSDE220 became more accurate where the percentage error was within +/-4% of the AWTD. In addition, the acquired axial CT images were reconstructed both with and without a single energy metal artifact reduction algorithm (SEMAR), to study the effect on Dw. The Dw calculations used to determine SSDE220 varied by less than 0.2% between the images reconstructed with and without the metal artifact reduction algorithm. For the majority of the scans percentage error observed with 100 kVp is less than that with 120 kVp for SSDE204. Finally, a comparison of the manually calculated SSDE220 and that calculated by the Radimetrics software, showed an overestimation of SSDE values reported by the software compared to the manually calculated measurements which is due to an underestimation of Dw values calculated by the software. This underestimation resulted from including the slices effected by the cone beam artifact in SSDE calculations.

Bioenergetics of lotic filter-feeding insects Simulium spp. (Diptera) and Hydropsyche occidentalis (Trichoptera) and their function in controlling organic transport in streams

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCullough, D.A.; Minshall, G.W.; Cushing, C.E.

1979-06-01

This study derives a set of bioenergetic parameters for the blackfly Simulium spp. (Diptera: Simuliidae) and the caddisfly Hydropsyche occidentalis (Trichoptera: Hydropsychidae) and evaluates the impact of these filter feeders on the lotic environment. In addition, comparison is made between field- and laboratory-derived estimates of ingestion and between 2 methods of calculating assimilation rate. Digestion (gut-clearance) time for Simulium ranged between 0.33 and 1.25 h compared to 1.54 to 2.63 h for Hydropsyche. Mean ingestion rate for Simulium in a series of experiments ranged from 1.36 to 54.74 ..mu..g DW/mg DW/h. The mean assimilation efficiency for diatoms was about 55%more » as measured by the dual-label technique. Mean ingestion rates of diatoms for Hydropsyche in 3 experiments were 31.3, 31.0 and 29.2 ..mu..g DW/mg DW/h, respectively; low values (3 ..mu..g DW/mg DW/h) from a 4th experiment were associated with high concentrations of green algae. An assimilation rate for diatoms of 7.5 ..mu..g AFDW/mg DW/h was derived for Hydropsyche. Measurements of growth rates of Hydropsyche under natural conditions were 3.6 to 4.4 ..mu..g DW/mg DW/h. Respiration rate of Hydropsyche for water greater than or equal to 62% O/sub 2/ saturation was about 2.3 ..mu..l O/sub 2//mg DW/h at 20/sup 0/C. The results of this research in combination with literature derived values, yielded the following mean energy budgets for Simulium and Hydropsyche, respectively(J/mg/h): ingestion (C) 0.318, 0.393; respiration (R) 0.092, 0.042; growth (G) 0.092, 0.100; assimilation (A) (as C x AE) 0.182, 0.192; (as G + R) 0.184, 0.142 (values times 0.239 = cal/mg/h).« less

Near-field interaction between domain walls in adjacent permalloy nanowires

NASA Astrophysics Data System (ADS)

O'Brien, Liam

2010-03-01

A domain wall (DW) moving in a ferromagnetic nanowire may interact with the stray field from another DW travelling in an adjacent wire. This could greatly impact the operation of proposed DW based data storage schemes which rely on the controlled propagation of DWs in densely packed nanowires [1, 2]. Here we experimentally study the interaction between two DWs travelling in adjacent Permalloy nanowires [3]. We find that the interaction causes significant pinning, with measured pinning fields of up to 93 Oe (˜5 times the intrinsic pinning field of an isolated wire) for the smallest separations. We present an analysis of the observed pinning field dependence on wire separation in terms of the full magnetostatic charge distribution within a DW. By considering an isolated DW, and accounting for finite temperature, it is possible to fully reproduce the experimentally observed dependence. This suggests that the DW internal structure is not appreciably perturbed by the interaction and so remains rigid, consistent with a finite sized quasi-particle description [4]. The full charge distribution must be considered in understanding these near-field interactions as other models based on simpler descriptions of the charge distribution within the DW, including a point-like distribution, cannot reproduce the observed dependence. Finally, we develop the idea of using localized stray fields to pin a DW and show how specific potential landscapes can be created by tailoring a pinning charge distribution, with the added advantage that neither DW internal structure nor nanowire geometry is appreciably perturbed. [4pt] [1] Allwood, Cowburn et al. Science 309, 1688 (2005) [0pt] [2] S. S. Parkin, Science 320, 190 (2008) [0pt] [3] O'Brien, Cowburn et al. Phys. Rev. Lett. 103, 7, 077206 (2009) [0pt] [4] Saitoh, Miyajima et al. Nature 432, 203 (2004)

Human Hair, Baltic Grey Seal (Halichoerus grypus) Fur and Herring Gull (Larus argentatus) Feathers as Accumulators of Bisphenol A and Alkylphenols.

PubMed

Nehring, Iga; Staniszewska, Marta; Falkowska, Lucyna

2017-05-01

The purpose of the study was to determine the concentration of bisphenol A (BPA), 4-tert-octylphenol (OP), and 4-nonylphenol (NP), in human hair, the fur of Baltic grey seals and the feathers of herring gulls. Hair was collected from 42 volunteers, while grey seal fur (n = 17) came from the seal centre in Hel (Marine Station of Institute of Oceanography, University of Gdansk) and gull covert feathers (n = 26) were collected from dead herring gulls along the Southern Baltic coast. Assays of phenol derivatives were conducted using the high performance liquid chromatography with fluorescence detection technique. In human hair, the mean BPA concentration amounted to 411.2 ng g -1  dw, OP 131.2 ng g -1  dw, NP 4478.4 ng g -1  dw, in seal fur BPA 67.5 ng g -1  dw, OP 62.8 ng g -1  dw, NP 39.1 ng g -1  dw, and in feathers BPA 145.1 ng g -1  dw, OP 162.0 ng g -1  dw, NP 37.7 ng g -1  dw. The increase of the analysed EDCs in hair was significantly influenced by diet rich in products of marine origin, as well as hair colouring, heating up food in plastic containers, using home cleaning products without protective gloves and wearing newly purchased clothes without washing them first. The concentration of phenol derivatives in seal fur was influenced solely by the uniform diet rich in fish. In birds, the feeding area during molting significantly influenced the concentration of BPA, OP and NP found in covert feathers.

Separation of extra- and intracellular metabolites using hyperpolarized 13C diffusion weighted MR✩

PubMed Central

Koelsch, Bertram L.; Sriram, Renuka; Keshari, Kayvan R.; Swisher, Christine Leon; Van Criekinge, Mark; Sukumar, Subramaniam; Vigneron, Daniel B.; Wang, Zhen J.; Larson, Peder E.Z.; Kurhanewicz, John

2017-01-01

This work demonstrates the separation of extra- and intracellular components of glycolytic metabolites with diffusion weighted hyperpolarized 13C magnetic resonance spectroscopy. Using b-values of up to 15,000 s mm−2, a multi-exponential signal response was measured for hyperpolarized [1-13C] pyruvate and lactate. By fitting the fast and slow asymptotes of these curves, their extra- and intracellular weighted diffusion coefficients were determined in cells perfused in a MR compatible bioreactor. In addition to measuring intracellular weighted diffusion, extra- and intracellular weighted hyperpolarized 13C metabolites pools are assessed in real-time, including their modulation with inhibition of monocarboxylate transporters. These studies demonstrate the ability to simultaneously assess membrane transport in addition to enzymatic activity with the use of diffusion weighted hyperpolarized 13C MR. This technique could be an indispensible tool to evaluate the impact of microenvironment on the presence, aggressiveness and metastatic potential of a variety of cancers. PMID:27434780

Depinning transition of a domain wall in ferromagnetic films

DOE PAGES

Xi, Bin; Luo, Meng -Bo; Vinokur, Valerii M.; ...

2015-09-14

Here, we report first principle numerical study of domain wall (DW) depinning in two-dimensional magnetic film, which is modeled by 2D random-field Ising system with the dipole-dipole interaction. We observe non-conventional activation-type motion of DW and reveal the fractal structure of DW near the depinning transition. We determine scaling functions describing critical dynamics near the transition and obtain universal exponents establishing connection between thermal softening of pinning potential and critical dynamics. In addition, we observe that tuning the strength of the dipole-dipole interaction switches DW dynamics between two different universality classes, corresponding to two distinct dynamic regimes characterized by non-Arrheniusmore » and conventional Arrhenius-type DW motions.« less

Synthesis of Mg(OH) 2, MgO, and Mg nanoparticles using laser ablation of magnesium in water and solvents

NASA Astrophysics Data System (ADS)

Phuoc, Tran X.; Howard, Bret. H.; Martello, Donald V.; Soong, Yee; Chyu, Minking K.

2008-11-01

Laser ablation of magnesium in deionized water (DW), solutions of DW and sodium dodecyl sulfate (SDS) with different concentrations, acetone and 2-propanol has been conducted. The results showed that ablation in acetone and 2-propanol yielded MgO and Mg nanocrystallites as isolated particles and agglomerated chains probably intermixed with organic residues resulting from the alteration/decomposition of the solvents under the high-energy conditions. Brucite-like Mg(OH) 2 particles were mainly produced by laser ablation of Mg in either DW or DW-SDS solutions. Ablation in DW yielded particles of fiber-like shapes having a diameter of about 5-10 nm and length as long as 150 nm. Materials produced in DW-SDS solutions were composed of various size and shape particles. Some had rough surfaces with irregular shapes. Small particles were about 20-30 nm and larger particles were about 120 nm. Particles with rod-like, triangular, and plate-like shapes were also observed.

Proximate and polyphenolic characterization of cranberry pomace.

PubMed

White, Brittany L; Howard, Luke R; Prior, Ronald L

2010-04-14

The proximate composition and identification and quantification of polyphenolic compounds in dried cranberry pomace were determined. Proximate analysis was conducted based on AOAC methods for moisture, protein, fat, dietary fiber, and ash. Other carbohydrates were determined by the difference method. Polyphenolic compounds were identified and quantified by HPLC-ESI-MS. The composition of dried cranberry pomace was 4.5% moisture, 2.2% protein, 12.0% fat, 65.5% insoluble fiber, 5.7% soluble fiber, 8.4% other carbohydrates, 1.1% ash, and 0.6% total polyphenolics. It contained six anthocyanins (111.5 mg/100 g of DW) including derivatives of cyanidin and peonidin. Thirteen flavonols were identified (358.4 mg/100 g of DW), and the aglycones myricetin (55.6 mg/100 g of DW) and quercetin (146.2 mg/100 g of DW) were the most prominent. Procyanidins with degrees of polymerization (DP) of 1-6 were identified (167.3 mg/100 g of DW), the most abundant being an A-type of DP2 (82.6 mg/100 g of DW).

Behavior of radioactive cesium during incineration of radioactively contaminated wastes from decontamination activities in Fukushima.

PubMed

Fujiwara, Hiroshi; Kuramochi, Hidetoshi; Nomura, Kazutaka; Maeseto, Tomoharu; Osako, Masahiro

2017-11-01

Large volumes of decontamination wastes (DW) generated by off-site decontamination activities in Fukushima Prefecture have been incinerated since 2015. The behavior of radioactive cesium during incineration of DW was investigated at a working incineration plant. The incineration discharged bottom ash (BA) and fly ash (FA) with similar levels of radiocesium, and the leachability of the radiocesium from both types of ash was very low (<1%). These results are significantly different from those obtained for the incineration of contaminated municipal solid waste (CMSW) reported in earlier studies. The source of radiocesium in DW-FA is chiefly small particles derived from DW and DW-BA blown into the flue gas, not the deposition of gaseous synthesized radiocesium compounds on the surfaces of ash particles in the flue gas as observed in CMSW incineration. This source difference causes the behavior of radiocesium during waste incineration to differ between DW and CMSW. Copyright © 2017 Elsevier Ltd. All rights reserved.

Assessing the distribution, origins, and ecological risk of polycyclic aromatic hydrocarbons (PAHs) in the habitat of Medaka fish at Keramat Kebo River and Estuary, Tangerang, Banten

NASA Astrophysics Data System (ADS)

Falahudin, D.; Yogaswara, D.; Khozanah; Edward

2018-02-01

Indonesia has a variety of coastal systems such as coral reef, mangrove, seagrass, mudflat, and dune, each of which has high biodiversity of species. The primary concern in Indonesia is that rapid economic growth would endanger some essential natural ecosystems and resources, and cause deterioration of environmental condition. As a part of bioindicator development to recognize pollutants with small fish of the genus Oryzias, this study was conducted to assess baseline status of PAHs distribution and sources in seawater, sediments and Oryzias fish. The ecological risk of PAHs in sediments was also evaluated. Concentrations of fifteen USEPA PAH based on GCMS analysis in seawater, sediments, and Oryzias fish vary from 0.00 to 30,600 ng/l, 6.7 to 138.6 ng/g dry weight (dw) and 25.2 to 30.5 ng/g dw, respectively. Based on the diagnostic ratio of PAH compounds, the potential sources of PAHs originated mainly from pyrogenic sources. The status of sediment from this Oryzias fish habitat was considered to be low polluted with PAHs.

Enhancing EPA Content in an Arctic Diatom: A Factorial Design Study to Evaluate Interactive Effects of Growth Factors.

PubMed

Steinrücken, Pia; Mjøs, Svein A; Prestegard, Siv K; Erga, Svein R

2018-01-01

Microalgae with a high content of the omega-3 polyunsaturated fatty acids (PUFAs), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) are of great demand for microalgae-based technologies. An Arctic strain of the diatom Attheya septentrionalis was shown in previous experiments to increase its EPA content from 3.0 to 4.6% of dry weight (DW) in the nutrient-replete exponential phase and nutrient-depleted stationary phase, respectively. In the present study, a factorial-design experiment was used, to investigate this effect in more detail and in combination with varying salinities and irradiances. A mathematical model revealed that both growth phase and salinity, alone and in combination, influenced the EPA content significantly. Maximum EPA values of 7.1% DW were obtained at a salinity of 22 and after 5 days in stationary phase, and might be related to a decreased silica content, an accumulation of storage lipids containing EPA, or both. However, growth rates were lower for low salinity (0.54 and 0.57 d -1 ) than high salinity (0.77 and 0.98 d -1 ) cultures.

Arsenic uptake and speciation in the rootless duckweed Wolffia globosa.

PubMed

Zhang, Xin; Zhao, Fang-Jie; Huang, Qing; Williams, Paul N; Sun, Guo-Xin; Zhu, Yong-Guan

2009-01-01

Duckweeds are a common macrophyte in paddy and aquatic environments. Here, we investigated arsenic (As) accumulation, speciation and tolerance of the rootless duckweed Wolffia globosa and its potential for As phytofiltration. When grown with 1 microm arsenate, W. globosa accumulated two to 10 times more As than four other duckweed or Azolla species tested. W. globosa was able to accumulate > 1000 mg As kg(-1) in frond dry weight (DW), and tolerate up to 400 mg As kg(-1) DW. At the low concentration range, uptake rate was similar for arsenate and arsenite, but at the high concentration range, arsenite was taken up at a faster rate. Arsenite was the predominant As species (c. 90% of the total extractable As) in both arsenate- and arsenite-exposed duckweed. W. globosa was more resistant to external arsenate than arsenite, but showed a similar degree of tolerance internally. W. globosa decreased arsenate in solution rapidly, but also effluxed arsenite. Wolffia globosa is a strong As accumulator and an interesting model plant to study As uptake and metabolism because of the lack of a root-to-frond translocation barrier.

Research observation: Hydrolyzable and condensed tannins in plants of northwest Spain forests

USGS Publications Warehouse

Gonzalez-Hernandez, M. P.; Karchesy, J.; Starkey, E.E.

2003-01-01

Tannins are secondary metabolites that may influence feeding by mammals on plants. We analyzed hydrolyzable and condensed tannins in 30 plant species consumed by livestock and deer, as a preliminary attempt to study their possible implications on browsing and grazing in forest ecosystems. Heathers (Ericaceae) and plants of the Rose (Rosaceae) family had tannins, while forbs, grasses and shrubs other than the heathers did not show astringency properties. We found the highest tannin content of all the species in Rubus sp., with the highest value around 180 mg TAE/g dry weight in spring. Potentilla erecta, Alnus glutinosa and Quercus robur were next with 57 to 44 mg TAE/g dw. Total tannins in heathers ranged from 22 to 36 mg TAE/g dw. Levels of condensed tannins were higher than hydrolyzable for most of the species. Only Betula alba, Calluna vulgaris, Pteridium aquilinum and Vaccinium myrtillus had 100% hydrolyzable tannins. Tannin content of the species changed seasonally with highest values during the growing season, corresponding to late winter or early spring, depending on the species.

Research observation: Hydrolyzable and condensed tannins in plants of the northwest

USGS Publications Warehouse

Gonzalez-Hernandez, M. P.; Karchesy, J.; Starkey, Edward E.

2003-01-01

Tannins are secondary metabolites that may influence feeding by mammals on plants. We analyzed hydrolyzable and condensed tannins in 30 plant species consumed by livestock and deer, as a preliminary attempt to study their possible implications on browsing and grazing in forest ecosystems. Heathers (Ericaceae) and plants of the Rose (Rosaceae) family had tannins, while forbs, grasses and shrubs other than the heathers did not show astringency properties. We found the highest tannin content of all the species in Rubus sp., with the highest value around 180 mg TAE/g dry weight in spring. Potentilla erecta, Alnus glutinosa and Quercus robur were next with 57 to 44 mg TAE/g dw. Total tannins in heathers ranged from 22 to 36 mg TAE/g dw. Levels of condensed tannins were higher than hydrolyzable for most of the species. Only Betula alba, Calluna vulgaris, Pteridium aquilinum and Vaccinium myrtillus had 100% hydrolyzable tannins. Tannin content of the species changed seasonally with highest values during the growing season, corresponding to late winter or early spring, depending on the species.

Inhibitory effect of chlorogenic acid on digestion of potato starch.

PubMed

Karim, Zida; Holmes, Melvin; Orfila, Caroline

2017-02-15

The effect of the chlorogenic acid isomer 5-O-caffeoylquinic acid (5-CQA) on digestion of potato starch by porcine pancreatic alpha amylase (PPAA) was investigated using isolated starch and cooked potato tuber as substrates. In vitro digestion was performed on five varieties of potato with varying phenolic content. Co- and pre-incubation of PPAA with 5-CQA significantly reduced PPAA activity in a dose dependent manner with an IC50 value of about 2mgmL(-1). Lineweaver-Burk plots indicated that 5-CQA exerts a mixed type inhibition as km increased and Vmax decreased. The total polyphenol content (TPC) of peeled tuber tissue ranged from 320.59 to 528.94mg 100g(-1)dry weight (DW) in raw tubers and 282.03-543.96mg 100g(-1)DW in cooked tubers. With the exception of Désirée, TPC and 5-CQA levels decreased after cooking. Principle component analysis indicated that digestibility is affected by multiple factors including phenolic, dry matter and starch content. Copyright © 2016 Elsevier Ltd. All rights reserved.